The episode begins with Megan making a Y shaped incision on Wallace’s latest victim and finds a bomb implanted in the body in place of the spleen. Just then Yvonne calls her and uses some software to change her voice so that it sounds like a man’s. She tells Megan to get the bomb to her and she would release Lacey. She doesn’t want Megan to disclose anything to anyone else. Megan tells her that the police already know that someone else was helping Wallace. Yvonne hangs up the call. Curtis checks on Megan and Megan asks him to leave her alone. Dan Russell calls Kate and tells her that there is something more to the Wallace case and he tells her to cover things before it all blows up.
After all, she is the one who took the victory dance on this one! Kate goes to check on the autopsy and Megan is elusive with her answers. Kate tells her that she will take over the autopsy. But Megan has already removed the bomb and hides it in her purse. Kate sends Megan to examine their latest victim. Megan arrives at the crime scene and Tommy tells her that the victim is a 15 year old kid and is a Caucasian female. Megan is scared; she feels it is Lacey. But when Gross turns the body to reveal the face, Megan is relieved to see that it is not Lacey, but Tommy feels that he has seen the girl before. He remembers seeing her in Wallace’s office pictures. Gross tells him that she is Wallace’s daughter, Alyssa Wallace.
Just then Yvonne calls. She tells Megan to make the drop immediately. But Megan tells her that it will not be possible because it could look suspicious. She tells her to make the drop by 7pm. Gross tells Megan that the liver temperature proves that Alyssa was killed three hours ago; that is after her father was killed. He realizes that there is some else involved in this. But Megan asks him to keep this to himself and not tell anyone. Gross is nervous; but supports Megan and tells Tommy that the girl died late last night. He also implies that Wallace could have killed her. Megan again is not very forthcoming as she normally is and Tommy figures out that she is lying about something. Megan then goes to meet Karl Simmons at the hospital. But Simmons doesn’t remember seeing anyone with Wallace.
Gross calls Megan and tells her that he found some cellulose under Alyssa’s finger nails, but the results will take time. Tommy arrives at the hospital. He tells Megan that he followed her. He tells her that he heard her talking to Simmons and Gross. He knows that something is going on. He tells her that he knows about the other killer and that if she doesn’t tell him the truth, he will have to report it. Megan tells him about Lacey’s abduction and the bomb. She tells him that the killer is planning to blow up a plane. Tommy tells her that he will help her on this one. He also enlists Adam’s help. He wants Adam to make a list of cops they could trust. He tells Adam the whole story and also about her meeting with the killer.
They need to keep an eye on Megan but also make sure that they don’t get too close. He bugs her purse with a GPS locator and tells Adam to keep this off the books. Next, Megan is at the parking lot waiting for the killer. Adam tells Tommy that if they lose the suspect and a plane gets blown up, they will face criminal charges. Megan gets a message which tells her to keep walking. Tommy loses her but Adam is following the GPS. Just then a white van pulls up in front of Megan and Simmons steps out of it. He tases her and then renders her unconscious. The van drives off and Tommy alerts his guys.
At the lab, Kate presses Gross for answers and Gross tells her that Megan made him promise that he would not tell anyone about the involvement of the second killer. Kate wonders what is going on. She realizes that they are missing something. She tells Gross that she wants everything on the dead girl. In the van, Megan is conscious and she finds herself hand cuffed. She wants to know what Simmons’s role is in this whole thing. He tells her that he and Yvonne have been planning this for the last two years. The 6 vets they killed were test subjects and he was the one who was actually going to carry the bomb to the plane and blow it up. He says that he wants to do this for all the soldiers who fought in the war and the government did nothing to help them.
Adam is tracking the van and he tells Tommy that they have entered a single storied building. Tommy tells him to prepare the team. Simmons and Megan arrive at the building and Megan finally sees Lacey. Megan checks the monitor on Lacey and tells Yvonne that Lacey is hypoglycemic and she needs her insulin shot. But Yvonne tells her that she wouldn’t give it to her until she plants the bomb back in Simmons’s body. Megan is left with no choice and she agrees to do the surgery. Tommy and the team arrive at the building. They find the van and find the tracker and some of Megan’s stuff inside the van. They have been played. Tommy also finds insulin among the other things.
They leave the building. Adam is sure that they are going to be fired the moment they reach the precinct. It is sunrise and Megan stitches up Simmons. She then goes for her bag to get the insulin. Yvonne tells her that there is no insulin in the bag. Simmons had found the tracker and so he got rid of all her other stuff. She tells Megan that she was anyways planning to kill them. Tommy is on his way back and Kate calls him and tells him that the cellulose found under Alyssa’s nails is from teak and mahogany. It is not commonly found. She tells him that this could be from a lumber mill or a place where this is found. Adam gets a hit; he tells Tommy that one of the dead vets used to work at a lumber mill next to the airport.
Tommy heads to the mill. Yvonne checks on Simmons and sees that he is awake. Megan has managed to steal a blade and she tells Lacey that she is going to cut off the duct tape. She tells her to run the moment she tells her to and not look back. She tells her to keep running till she finds a safe place and then call 911. Megan then attacks Yvonne and a fight ensues. But Lacey is too weak to run. Yvonne overpowers Megan and is about to shoot her. Tommy arrives on time and shoots Yvonne. But Simmons is gone. He stumbles towards the car. He has to catch the flight which leaves in four hours.
Tommy and the team stop Simmons. Simmons is left with no choice and he presses the trigger; the car blows up. Simmons is dead. Next, Lacey is in the hospital and Tommy arrives to meet her. Tommy tells Megan that he made an offer to the DA and told him that he could take full credit for what happened and how they stopped an attack. In return he wants him to turn a blind eye on Megan, him and his team. The DA agreed and now he and Kate are at a press conference. Megan thanks Tommy for saving Lacey’s life. Megan introduces Tommy to Lacey as an old friend. The episode ends.