The episode starts on a Chicago dock in 1927, where Damien Darhk and the Reverse-Flash approach Al Capone and offer their services. He declines, sticking his men on him, but Thawne takes them out quickly.
They tell Capone that they can help him face some new foes coming to town soon — along with their new friend Malcolm Merlyn.
On board the Waverider, ATOM and Citizen Steel are sparring until Sara and Jax come in to make them stop. The pair leave, and Jax heads to the library, where he finds Stein thinking about his daughter. Jax warns Stein that eventually the team will find his daughter and try to get rid of her, but Martin says that she can be protected if her impact on history remains minimal.
The team gets called together when Gideon has found a temporal tremor coming from Chicago in 1927. They all suit up and head there, where Ray and Steel see Elliot Ness arriving. They deduce that maybe somebody has tipped off Capone that Ness will be a threat, and decide to protect him.
Ray follows Ness, but when a pair of Chicago police officers offer to accompany Ness to the FBI, Ray leaves them alone. It turns out the cops were crooked, and back on the ship, they discover that as a result of killing Elliot Ness, Capone becomes mayor of Chicago instead of going down for tax evasion.
Nate figures out that Capone will likely be trying to kill ness by drowning him off Dock 39, so they go stop him from being killed. As they’re trying to resuscitate an unconscious Ness, Damien Darhk looks on, pleased that the Legends “took the bait.”
On board the Waverider, it’s going to take a while to heal Ness, so Nate decides to impersonate Ness and continue his investigation. They decide they’re going to take down one of Ness’s clubs. Sara, Jax, and Stein decide to go undercover at the club.
On the ship, Mick is miserable. Amaya tries to get him to open up to her, but he won’t. After a couple of drinks, he sees Snart, who mocks him for working with the Legends, and says he’s there to set Mick straight.
Inside the club, the team sees Darhk. Before they can react, Thawne shows up and kidnaps Sara and Stein, and leaves the rest of the team looking embarrassed when “Ness” raids a bar that’s already been cleaned out of its booze.
On board the Waverider, the team argues about how to nail Capone, while plotting how to use Rip’s armory to chase down the speedster. Mick finally tires of hearing them argue and decides to take charge.
In a basement, Sara and Stein are tied up. Merlyn comes in to tell Sara that if she gives him the amulet Thawne wants, he will give her a life again: he’ll prevent the sinking of the Queen’s Gambit. She declines the offer, telling him that time is sacred and it can’t be changed to suit any one person’s desire without hurting others.
As he leaves, she tells him that she’ll take a nightmare that’s real over a dream that’s a lie. When Stein praises her selflessness, she says she owes him for teaching it to her.
On a road outside Chicago, one of Capone’s trucks is stopped in its tracks when Mick and Amaya shoot it up and steal it.
Back in the basement, Sara is frustrated by the thought of Merlyn changing time. He tells Sara that even the best of them can create havoc. He admits that he accidentally created a daughter. Sara is angry, insisting that Lily isn’t real, but Stein says that now that his memories have set, she is real. Before they can finish their conversation, Darhk comes in and tells Sara that they plan to torture Stein. They carry him away and throw him in a cell with Thawne, who takes out a futuristic box, saying he’s modified a lethal weapon to be only a pain-inducing one.
At the destination of the delivery truck, Nick, Amaya, Ray, and Nate arrive to look for Capone’s documents. Once there, Amaya finds Sara and sets to work freeing her. Nate and Ray steal Capone’s ledger. Rory is working his way through the halls, where he again sees Snart trying to convince him to abandon the team.
The Legends find Stein and they’re getting ready to leave when Capone and his men arrive. After a brief scuffle, the Legends get away — but Capone smiles, and Darhk comes out to tell him how glad Thawne is going to be for his good work.
Back on the Waverider, the team is celebrating an apparent win but nobody is sure what to do next. Stein suggests that he should take a look at the amulet Darhk and Merlyn wanted, and that confuses Jax a little.
After a quick conversation with Amaya, Mick sees another Captain Cold vision. Jax sees the speedster doing his thing in the library.
Sara is in the library, too, and accidentally reveals to Thawne that Stein has a daughter that might be leveraged against him. When the rest of the team tries to get Sara away from “Stein” to deal with the issue, Thawne gets wise. After a short fight, Thawne gets free on the bridge, opening the cargo bay for Merlyn and Capone’s men to come on board while Ray and Nate are locked in a storage room.
Elsewhere in the ship, Capone’s men are firing off guns while Sara tries to defend her position. Ray and Nate show up to help out.
Mick stages a theft of the amulet, but uses it as a chance for Amaya to blast Thawne with he speed gun. Meanwhile, Sara and Merlyn fight on the bridge.
Thawne gets away and is about to kill Amaya, but his watch goes off and he decides to run instead. Sara is ready to cut Merlyn’s throat, but he buys himself time by offering up Stein.
Back at the docks, Capone and his men are about to toss Stein into the river when Sara shows up and knocks Capone out. She reveals that she gave Thawne the amulet.
In a park, Ray and Nate hand over Capone’s ledger to Ness.
On board the Waverider, Mick is talking to “Snart” when Amaya comes to see him in the lunchroom. She brings him a bottle of Canadian whiskey she stole from Capone’s warehouse. She leaves, though, and Cold continues to mock Mick.
In the library, Stein and Sara talk about how “some things are more important than history,” which is why she decided to save him at a potential cost to history — and why she’ll protect Lily, too.
The Legion of Doom assemble to put two amulets together. It’s apparently a map that will bring them to the Spear of Destiny — a powerful, magical artifact…and to get it, the’ll need Rip Hunter.
Cut to 1967, where Rip — without an English accent — is directing a film that seems to be the life story of Rip Hunter, Time Master.