Nate and Sophie take refuge by an outdoor pool and Sophie complains that they should have just gone to the movies like she said. He points out that she would be in jail but she thinks that's preferable to being dead.
Nate gets word from the others that they're staying in DC and tells Sophie that they have two days off. She wants to go to a murder movie festival and Nate wants to go once they're running a movie with early forensics. However, Sophie explains that he'll have to go on his own while she tries to straighten out matters at her theater.
The next day, Sophie goes to an art auction at the manor of the recently-deceased millionaire Jonas Gault. As Jonas' art curator, Katrina Hardt, shows them to Sophie, one of Jonas' daughters, Fiona, is arguing with Gault's fourth ex-wife Eleanor, who is drinking. Once Katrina leaves, Jonas' son Woodman introduces himself to Sophie and explains that he reacquainted himself with his father in his last year. He insists that he's met Sophie somewhere before. Paolo, Jonas' former manservant, comes by and takes Sophie's drink. When Woodman continues to insist he knows Sophie, Nate comes in and assures him that Sophie is from overseas. Once they're alone, Nate realized that she was up to something and explains that he deduced her location from among the major events in the area. He wonders why she lied and is at an art auction, and Sophie claims that she's a fan of the artist, Jean Mettier.
After the auction, Katrina and explains that Jonas assembled all of Mettier's work. She tells the crowd that the family lawyer, Reinhold Shecter, and Fiona have arranged for the auction. Sophie insists that there's nothing to stay for, but Shecter announces that there will be a special showing of Mettier's first painting, Ma Mystere
. Sophie has a ticket and they go down to the vault. She tells Nate that it's personal but won't explain further. Fiona announces that Jonas kept the painting locked in the vault and he was the only one who ever looked at it. Shecter opens the vault and they discover that the painting is gone.
Nate immediately grabs Sophie and drags her out, pointing out that she'll be the first suspect. He doesn't believe that she's innocent and they head for the door... just as Sterling stops them. he tells Sophie to hand over the painting and has his agents take them into custody. When Nate points out that Interpol has no authority there, Sterling explains that art theft falls under his jurisdiction because it's used to fund terrorism. Interpol plans to choke off the money at the source and Sterling is in charge of that operation. Nate insists that it's just a coincidence but Sterling doesn't believe it. He demands to know where the painting is but Nate points out that he has no evidence that they were involved. Sterling threatens to keep them there until he does get the proof and his agents handcuff Nate and Sophie together. When Nate reminds Sterling that he owes him, Sterling says that's the only reason he's bothering to look for evidence.
Once they're alone, Nate and Sophie quickly free themselves and Sophie blames Nate for getting involved. He wonders what's going on but Sophie avoids the question. They slip out and Sophie insists that the theft was an amateur job and beneath her. Nate figures that they have to find the real thief and hand them over. They find Shecter and claim to be undercover Interpol agents. He explains about the security procedures, including a tag that would have gone off when the painting was moved. Woodman was disowned later so Fiona and Eleanor would split the insurance settlement. Once Shecter leaves them alone, Nate examines the alarm system and realizes that it would have taken two days to break in. He realizes that Shecter's hand was sticky from a spilled drink and applies face powder to the keypad to find out the combination. While they work, Sophie complains that Nate didn't trust her.
They discover that Shecter used a different combination then the ones that matches the worn keys. They figure that someone had access to the vault and changed the combination. They go to Jonas' room and talk to Paolo, and Sophie spins a tale of how Jonas sent her flowers when she turned 16. Once they're alone, Nate points out that Jonas' glasses are on the wrong side of the bed. They check his printer buffer and discover that it holds a record of access times to the vault. On the day of his death, there were six unexplained entries and exits into the vault. Jonas changed the combination and then died, and Nate and Sophie both realize that it's murder.
Nate and Sophie take what they have to Sterling and show him that according to the prescription information, dozens of pills went missing on the day Jonas died. They go to the plumbing and remove the filter, revealing the empty gel caps. Sterling figures the killer would have constant access, meaning they're a member of the household: Katrina, Shecter, Fiona, Eleanor, or Woodman. Sterling gives them an hour to find the guilty party or he'll arrest them both.
Sophie starts with Katrina, who confirms that Jonas had her there every day, including the day he died. She says that she was arguing with Fiona while Jonas slipped away. Fiona was going to fire Katrina because she didn't think that they need a full-time art curator.
Next, Sophie and Sterling talk to Fiona, who admits that she was dealing with Eleanor on the day of her father's death. Eleanor insisted that Jonas trusted her more than Fiona, and Fiona promised that Eleanor wouldn't get a dime. When Sophie talks to Eleanor, the ex-wife claims that they had grown closer after their divorce and they were going to get remarried. Shecter had told her that Jonas wanted to get remarried in his last days but asked her not to tell anyone.
Shecter claims that there were no plans for a new marriage and tells Sophie that Jonas had made a decision to add Woodman back into the will for a full share. However, Woodman didn't want it. Nate goes to find Woodman at the pool. The son explains that he ruined his life and Jonas kicked him loose. Woodman started a contracting company and offered to fix the pool just so he could be close to his father. He confirms that Katrina was up at Jonas' bedroom right after the maid found the old man dead.
Nate meets up with Sophie and Sterling and they try to figure out who had a motive. Everyone but Woodman and Shecter had a motive, and Nate figures that Shecter was embezzling. They all alibi each other for the times that the vault was open, leaving nobody. Nate leads them to Paolo's room and reveals that the painting is hidden beneath his bed. The Interpol agents take the manservant away while Katrina unveils the painting for the audience. She confirms that it's the real painting and Sterling figures that the matter is closed.
As Sterling walks away, Sophie tells Nate that it isn't the real painting. They go to the stable and talk privately, and Sophie asks Nate to trust her. She offers to prove it and Nate realizes that she wants to steal both the fake painting and one of the real Mettier paintings sold earlier so she can compare them. Sophie wishes that he'd rather take her at her word but Nate refuses. He figures that he'll have to go through Sterling to get Ma Mystere
and comes up with a way to do it while Sophie steals one of the real paintings. They kiss and go their separate ways.
Sterling is having Ma Mystere
crated up when Nate comes in and hints that his former partner has missed something. A paranoid Sterling seizes on the idea and figures that Nate has realized how he'll mess the investigation up, and orders everyone to secure the paintings while they go back to the beginning and check everything.
Katrina is supervising the shipment of the paintings outside. Once she leaves, Sophie approaches the shipping representative, Frank, and claims that one of them is hers. She asks for "her" painting and the man demands an ID. Sophie then goes over to Katrina and has a whispered conversation about the security. She tells the curator that she wanted Frank's contact info but he wouldn't give it to her. Katrina calls over to Frank to give it to Sophie and he assumes that she means the painting.
Nate prowls around Paolo's room and Sterling gives hot and cold hints before leaving. The Interpol agent tells one of his agents to follow Nate and then starts desperately searching. Meanwhile, Nate goes into the kitchen and starts a fire, and then goes back to the study where Ma Mystere
is stored. He hands the real painting out to Sophie, who is waiting with another identical box. When the Interpol agent comes in, Nate claims that he's lost his phone.
Back at the stable, Sophie and Nate examine Ma Mystere
and he tests the samples from the two paintings. Using a crude spectrometer to analyze the gas, Nate tells Sophie that they match. She insists that they can't be real and Nate wonders what she thought it would be. Sophie doesn't answer and Nate suggests that there is one other possibility: the other painting is also a forgery. When Sophie points out that the stolen painting came from Gault's collection and it's unlikely she stole the one fake among them, Nate figures that they're all fakes.
Nate and Sophie to go Sterling and tell them what they've discovered. He's understandably skeptical and tells his people to arrest them both, but they point out he has nothing to arrest them with. Sterling wonders how someone could have pulled it off, repainting every single painting, and Nate says that Jonas was half-blind, giving the forger months. The only one with the knowledge and the ability to forge fake provenance papers was Katrina. Sterling goes out and asks if anyone has secretly been replacing the Mettiers with fakes. Katrina runs for it immediately, much to Sterling's surprise, and they hear someone screaming by the pool. By the time they get there, they find Katrina dead in the pool.
Afterward, Sterling tells his team that Katrina must have slipped and fell. He's also happy that he knows Nate and Sophie are working out of Portland and wishes them well. Once he walks away, Nate and Sophie make a hasty exit. Back at the brew pub, the couple shares a drink and admits that it was just like old times. Sophie wishes she had gotten to see the Ma Mystere
and says that she can't tell Nate how she knew it was a fake due to personal reasons. She thanks Nate for his trust in her and he says that he does trust her. As they start to kiss, Nate explains that he noticed she was wearing high heels when she left. He then called all the high-end caterers and found out about the art auction. As Sophie goes to change, Nate gets an idea and realizes that he's been an idiot. When Sophie comes back, she discovers that Nate has left.
Nate goes back to the house and tries to put things together, since he's realized that Katrina couldn't have cracked the second alarm. Her accomplice draws a gun on him: Woodman. He assures Nate that the house is empty and no one will hear the gunshot. Nate figures that he went to art school in Paris and learned enough to make Mettier forgeries. When Jonas got sick, Woodman came home to scam some money and seduced Katrina. When she ran to him for help that afternoon, Woodman killed her with a brick and tossed her into the pool. The two of them switched out a painting every few months, and went after Ma Mystere
when Woodman saw the keypad and realized that he knew the combination. Since no one had ever seen Ma Mystere
, he figured that his forgery didn't have to be exact. However, Jonas saw Woodman and Katrina together, confirmed that someone was going in and out of the vault, and changed the combination.
Woodman prepares to kill Nate, saying he's not so smart. Nate points out that he's smart enough not to kill his partner. Sophie storms in and hits Woodman with a vase, and they run out to the outdoor pool and Sophie complains that they should have just gone to the movies like she said. He points out that she would be in jail but she thinks that's preferable to being dead. Nate tells Sophie to run, then grapples with Woodman, handcuffs him with Sterling's handcuffs to the crate, and shoves him into the pool. They call in Sterling and assure him that they've captured all the guilty parties. Nate explains that Jonas changed the code after Woodman removed Ma Mystere
but before he could put the fake in. Then Woodman framed Paolo by planting the fake in the manservant's quarters. Sterling figures they'll get the real painting location's out of Woodman eventually. As he leaves, Sterling offers Nate a job any time he wants and even says he can bring Sophie along.
Sophie and Nate go back into the house and study the vault. She wishes she had seen Ma Mystere
just once, and Nate wonders how Woodman defeated the two-tiered security system. He reminds Sophie that Woodman was a contractor and then takes a crowbar to the fake wall that Woodman set up. The painting is a nude of Sophie, and she explains that Merrier vowed that no one would see it until after her death. She considers it a matter of honor to steal it to honor Merrier's wishes. Nate collects the painting and they leave, arm-in-arm.