In Paris,  Chloe, Abraham, and Jackson are in the sewers tracking bears. 

42 hours earlier, Jamie is being photographed for her fake passport. She needs a new identity because she killed an FBI agent. Abraham reminds her that she killed him in self-defense, but until they can figure out how to prove it, she needs talk to the focus on clearing her head. Jackson and Mitch decide that for now, they cannot take the Mother Cell to the government. Mitch thinks that they need more evidence first in order to build a stronger case. Chloe announces that bears are on the loose in Paris, so they are headed there. Jackson thinks this is perfect for the evidence they need. They just need to capture a bear, and check its blood for the Mother Cell. Mitch steps out to get something from the drugstore before the flight, but instead calls Reiden Global, wanting to bargain for the Mother Cell. 

In Paris once again, Mitch is taking the blood from the hibernating bear that we met last week. Mitch examines the bear's eyes, but no defiant pupil, which should rule out the Mother Cell. 

Jackson and Chloe head to talk to Paris government officials. Jackson tells them that the bears won't be acting like they normally would, and suggests that the bears are in the sewers, which is why they haven't been seen by humans. Chloe is proud of Jackson for motivating them, and getting them to look in the right places. A civil engineer, Jean-Michel, wants to talk to Chloe about the bears, but she refuses to give him additional information. Jean-Michel encourages Chloe to call her sister, but she refuses. Jackson gathers from their conversation that he is Chloe's ex-fiance. 

Back at Chloe's house, Abraham is looking for some french wine, and Jackson and Mitch are talking bears. Jackson is baffled by the lack of the defiant pupil in the bear. Mitch suggests that the bear is changing, like a caterpillar turning into a butterfly. But what is the bear becoming? Chloe is searching for towels for her guests when the door swings open, and she sees her wedding dress. She gets a message to meet Delavane, and quickly hurries past Jackson, who sees the dress.

Abraham brings wine to Jamie, who is trying to get used to her new name. Abraham shares with Jamie that he once had a different name as well. He was taken in by rebels as a teenager after his parents were killed. During his initiation, they gave him a single bullet and a gun, and told him that he must choose which of his brothers to kill. He needed to shoot one, or both would be killed. Rather than be turned into an animal, Abraham chose not to kill either, and both of his brothers were killed in front of him. He escaped the rebel army years later, and changed his name, and vowed to protect those he cares about, his new family. 

Chloe tells Delevane that the team killed an FBI agent. He wants her to turn Jamie in, noting that the FBI will not stop until they find out who killed the agent. Chloe understands.

Abraham comes up with an idea. The team would break into Reiden Global's Paris office, and prove that Ben Schaffer was on their payroll by hacking their system. This will prove Jamie's innocence.

They start their Oceans Eleven style heist. Mitch and Jamie both hack their computers into Reiden's network. Jamie finds an executive in finance due to a handy corporate photo directory. Chloe can't get past a security guard whom she knows, so Jackson takes over. Using his cell phone, he fast talks the executive by telling him he's won a trip to Africa, all the while, filming him on his cell phone. Jamie then takes the footage and uses facial recognition to hack into their system, because Reiden doesn't just use passwords. The records she uploads head to Mitch's computer at the animal lab. 

Mitch gets the results back from the bear's blood test, and it confirms his suspicions. The bear is changing. The bear begins to wake up. Mitch attempts to give it a sedative, but the bear's skin has become tough, like armor. He checks the bear's pupils again, and there it is. The defiant pupil. The bear wakes up, swipes at Mitch, and escapes the lab. 

Mitch put a microchip into the bear, so Jackson, Chloe and Abraham head after the bear, as Mitch guides them where to go based on its location. Jamie heads to the lab to be with Mitch, and make sure that he is okay after being knocked down by the bear. Mitch explains to them that the bear has developed a strong exoskeleton. When they arrive at the bear, French animal services is already there, Jean-Michel, specifically. He wants Chloe to explain why the bear has such thick skin, and what her agency is really doing. Jackson finds a man in the woods who has been dead for days, so it appears that the loose bears have been hunting. 

They find a sewer entrance, and Jean-Michel goes in with them, familiar with the underground maze, being a city engineer. They find the sleuth of bears, sleeping, but there are only 2. 1 is still missing.  They go on to find the third, but on their way out, they notice that the other two bears are gone, and ready to attack. Jackson warns them not to run, and to stand still. Jean-Michel doesn't listen, and runs, and is knocked down by a bear. Jackson fires at the bear, and after 2 darts, sedates the bear, and goes back to help Abraham do the same with his bear. 

Now safe, Chloe asks Jean-Michel to be good to her sister, better than he was to her. 

Back at the lab, Mitch explains what he thinks the Mother Cell is doing. The Mother Cell is speeding up animal adaptations, changes that would have happened organically over time. He also thinks that the Mother Cell can slow down the changes, if he is given time to create a vaccine. 

Chloe shares the good news with Delevane, and tells him that now that she knows what is happening, she is going to continue to do her job with every member of her team. She won't cut Jamie loose. 

Mitch secretly meets with Clayton Burke from Reiden Global. The Mother Cell is accelerating her cancer. Mitch wants Burke to get the trial drugs to him that will save Clementine ASAP, and he'll hand over the Mother Cell.