The scene opens with Fargo and Holly on Titan. They have a task to do and Fargo jokes around a little. Suddenly Holly’s tube loses pressure and Fargo says that he is sorry. The simulation ends and Dr. Huggins tells them if they fool around like that on Titan and they are going to be dead. Fargo tells him that he was just a little punchy from doing it all day. Fargo asks why he has to vent the atmosphere every time. He says that it has to be perfect. Dr. Huggins says that he has to leave now because Tiny is coming back from her mission to Titan. Fargo tells that Tiny almost vaporized them at one point and Dr. Huggins says that Tiny is his hero and Fargo jokes that Dr. Huggins needs to get out more and Dr. Huggins tells them that they need to flirt less. Meanwhile, Dr. Leonardo shows Henry and Grace her flowers that change color and they tell that they are nice. Jack comes in and asks what he can do as Best Man. Grace tells him that he prepare a toast because last time he rambled. Henry tells him not to lose the rings last time too. Grace tells Henry that she wants to get new rings and he agrees. Jack looks at the flowers and Dr. Leonardo flirts with him a little. Jack gets embarrassed and twirls around fast when Allison comes in. She tells Jack that since they are now seeing each other, she was required to fill out a form. She tells that their relationship has been “Red Flagged”. Warren Hughes, from the Department of Defense introduces himself to Jack and says that he is going to be there to monitor them.
Jack and Allison go to the landing bay to wait for Tiny’s return. Jack doesn’t like the whole thing and Allison says that they just have to get through the day. Warren asks what is going on and Allison says that Tiny, their rover, is coming back from building a landing bay on Titan so that they can facilitate the FDL. Dr. Huggins says that she is also bringing back some samples so that he can make the Titan simulation more real. Allison goes up to Henry and addresses him as Dr. Deacon. She tells him to activate return home sequence. It works, but when Henry takes off the shield, Tiny blows up. Afterward, Allison springs into action and asks if Warren is alright. He says that he is fine. Henry goes up to Allison and tells that it is possible that Tiny took in the chemicals on Titan, but they are not sure yet. Allison goes up to Jack and tells him to check the area, Warren volunteers to go with him. He tries to object, but thinks better of it. Meanwhile, Fargo apologizes to Holly for messing up back in the simulation. She tells that there is only one thing to do in this situation. She tells that they have to have sex. She offers herself and Fargo gets a call that he has to go.
Jo has Zane sign the paperwork he needs to be able to leave Eureka and have a full pardon of his crimes. He thanks her and says that she has done him a big favor. He says that he can leave Eureka. She asks if he is leaving and he says that he doesn’t know, but says that this could be the last time they see one another. They kiss and start to get “busy”. Meanwhile, Jack is in the woods with Warren who is asking him personal questions of Allison and his relationship. Jacks says that is none of his business when suddenly they see red smoke. Back at the landing pad, Grace asks if he is happy about getting married and he says that he is. Jo comes up and asks if they need any help with the wedding. Grace says that it is going to be a simple wedding. Back in the forest, they find the containment unit and Warren sees a part of Tiny. Suddenly the ground that Warren is standing on gives way and he falls. Jack comes up and pulls Warren up. He takes him back to the Infirmary and Allison tells that Jack almost broke the auditor and Jack tells that the audit is ridiculous. Warren says that Jack is a little testy and Allison says that he is level headed. Warren says that she and Jack make a weird couple because she is a genius whereas Jack is not. Allison says that he is smart and Warren makes a note.
Jack goes down to see Henry and Grace and asks about what he saw. Henry says that it was Ethane gas. Jo comes in with wedding books. She bombards her with options for the wedding. Jack tells that Jo is going a little crazy and she tells that it is a special thing. Jo tells that she has a florist that she needs to look at now. Fargo asks Zane what about Jo and he says that Jo is not asking him to stay, He asks Zane about the fact that Holly wants to “upgrade” their relationship. He says that he is not sure about it because he hasn’t courted her or anything. Zane says that there is nothing wrong with what Holly wants and says that he should go for it.
Jack talks to Henry and asks if it is possible that the area of the methane gases could have spread. Henry says that it is possible. Henry talks about how nervous he is now because Grace wants new rings and that he now has to match up with the old Henry. A signal goes off and Henry says that it has spread to Dr. Leonardo’s lab. Jo, Grace and Dr. Leonardo are walking through her herbal lab when they see a chemical coming through the vents. They pass out from the toxins. Jack and Henry race over to the lab and find the three women. Jo tells Jack to turn the valve and it sucks out the toxins. Meanwhile, Fargo meets Holly in the hallway and tells her that he doesn’t want to have sex with her. Henry and Grace get to Café Diem and Vincent has Angel Food Cake for them to try. Henry isn’t thinking of the cake and Grace asks him what is wrong. He says that he sees that she is still holding onto the old rings. He says that she is embracing him with one arm and holding onto another person with the other.
Back at Global Dynamics, Allison talks to Jack and says that Warren is talking to Jo about their relationship. He asks what she said about their relationship and she says that she told that it was progressing. Meanwhile, Warren asks Jo about Allison and Jack and she tells that Allison comes over and spends time with Jack at their house. Warren is intrigued and wonders why Jo, Jack and Allison are living in the same house. She tries to recant, but Warren says that he has all the information that he needs. Zane comes in and Joe asks why he isn’t gone yet. He says that he just wanted to say goodbye. They kiss and get “busy” again. Jack talks to Henry about the fact of all the methane and Jack realizes that Dr. Huggins overtaxed the chamber. He goes to Dr. Huggins’ lab and tells him to stop flushing the atmosphere. At the same time, Eureka’s Main Street is turning into Titan’s atmosphere. Henry has everyone get into Café Diem. Back at Jo’s office, they “finish” and Jo tells that Zane isn’t in any rush of going anywhere. They get the evacuation notice and Jo tells that she has to go.
Jack and Henry talk to Huggins who says that he has a portable device that should vent the vapors out. Fargo tells that he will go with Holly. On Main Street, Henry sees Fargo and Holly in the street and they are going to put the vents in place. Holly has a hard time getting her vent open and falls over. One of her tank’s pressure is dropping and Fargo keeps a level head and transfers her to her alternate tube. She thanks him and they get the vents in place. Meanwhile, Jack, Jo, Allison and Warren get to Dr. Leonardo’s lab and go inside. They try to pull the valve and Warren comes in and says that he can bench press more than his weight and manages to move the valve. Jack and Allison get the valve open and Eureka is safe. Later, Zane comes up to Fargo and tells that he should take his time with Holly and he agrees with Zane. Fargo tells Holly that he wants to have sex with her, but only after he has getting to know her. She agrees with that.
Henry asks if the atmosphere scared her of Titan and she says no, but the fact of her being away from Henry does. Jo pulls up and tells them to get in the car because she wants to show them something. She takes them to Henry’s garage and it is decorated and there are a few guests. They are happy and say that it is the perfect wedding. Warren is a reverend too and resides over the wedding. He tells Jack and Allison that he turned in his report and that the news is not good. Because they are a potential security risk for their relationship, it needs to stop or they will be fired from their posts. Henry and Grace renew their vows and Jack looks at Allison wondering what they are going to do now.