Cassie wishes Cole a Merry Christmas. The couple has been happy living in the past, but little did they know that was about to change.
While exchanging presents, Cassie jokingly gives Cole a razor begging him to shave. The two laugh together.
Cassie opens her gift from Cole to find a butterfly hair pin. Needless to say, she's incredibly touched he remembered her words, "Not every caterpillar becomes a butterfly."
She then presents Cole with his real gift, a simple Christmas card.
Cole opens it and learns he's going to be a father. "This is exactly where we're supposed to be" Cassie assures him and they kiss.
Unfortunately, during a quick visit to the local store time stands still. Cole walks outside and spots a woman, bleeding from the wrist. "It's not over James" she warns him.
Back at their little house of cedar and pine, Cassie and Cole discuss the red forest and the Witness. "What if it's not over?" Cole asks her. "We're still here. Your words. Time didn't collapse" Cassie replies. Still, Cole can't shake the vision of that mysterious woman and her message.
The next day time stops yet again, and Cole finds himself outside St. Mary's Mercy Asylum for the Insane. He enters and inquires about the woman he saw. The nun leads him to Lillian, who in over seventeen years had not had a single visitor. She also killed her entire family.
Lillian again warns Cole that the end is near. "Green to red" she tells him. Cole assumes the woman is Primary, especially after mentioning the Witness, Titan and the red forest. Lillian explains to Cole that the red forest has arrived in 1959. The end was near.
Cole drives out to the woods and sees a large red tree, surrounded by temporal anomalies. Lillian was right.
He returns to St. Mary's Mercy, where the mystery woman assures him he doesn't need a machine to time travel. "Go down the rabbit hole" she says and hands him the red leaves.
"Find the you in 1957, take control, undo your mistakes, stop the paradox and save us all" Lillian says. However, his time with Cassie will be erased as well.
"Death can be undone, James. Love cannot" she promises him.
With the temporal storms having arrived in 1959, Cole is left little choice but to go back to 1957 and rewrite history.
In the time stream, Cole revisits important moments from his life until he finally lands in 1957.
Cole kills the Messenger, Charlie, saving his wife's life and stopping the final paradox. Our heroes then find themselves back in the future with Jones.
Jones welcomes them home and shares what she remembers of her last days at the temporal facility. She then watched time repair itself.
The three ultimately use the time machine to jump over to Titan. Once there, they help Jennifer convince her "Daughters" to fight.
At Titan, the group overpowers the Army of the 12 Monkeys and saves their friends.
The surviving acolytes refuses to give up the whereabouts of the Witness, and Jones soon realizes Titan is actually a giant time machine. Elliot Jones, her ex-husband, built Titan for the Army of the 12 Monkeys.
The group attempts to leave Titan, when Cassie remembers the butterfly and her home with Cole in 1957. Love cannot be undone.
More acolytes appear, and a rogue member leads Ramse away from Titan to Olivia. She tells him his son is alive and waiting for him.
Cassie is kidnapped by another group of acolytes, while Jennifer is hit by a beam from the time stream. Cole is helpless to stop any of this.
Jennifer finds herself in the trenches of a battle in 1917 France.
Titan jumps away to the far future 2163, where a room full of masked acolytes awaits her. The Tall man is there.
"Where is the Witness?" Cassie demands from him.
"He's safe. One of two travelers outside of time. You brought him here Cassandra. The Witness is here... Mother" the Tall man informs her.
The Witness is Cole and Cassie's unborn child!