The episode begins with Dr. Nate Heywood, plowing his way through security at Star City Hall to see Mayor Oliver Queen. He tells Oliver that he needs to see him about Sara and Ray.
In Oliver's office, Nate tells him that the Legends are in trouble. He reveals that he knows Oliver is the Green Arrow, and tells him that he's a historian who specializes in "deductive historical reconstructions." He simplifies this to say he's basically a time detective.
He tells Oliver that he has been noticing subtle changes to history, and he believes the Legends are responsible. He believes that in 1942, before the invention of the atomic bomb, one went off underwater and may have killed the Legends.
Later, Oliver and Heywood take a sub into the Atlantic Ocean off the coast of New York and find the Waverider. Once they make their way on board, they find Mick in stasis in the medical bay, and decide to wake him up to ask what happened.
After a quick primer on what the Legends' mission statement has been, Mick talks about a trip to the day they were meant to safeguard King Louis XIII of France in order to prevent him from being killed before he can conceive his historically-significant son. While Ray, at tiny size, watches the king, Sara poses as a handmaiden to protect the queen. However, just as Ray, Mick, Rip, Stein, and Jax are fighting off time-traveling assassins, the queen seduces Sara. The team successfully defeats the baddies, but in order to do so, Ray and Firestorm both end up appearing in broad daylight in 16th Century France.
Back in the present day, Mick reveals to Oliver and Nate that the team had been warned away from 1942 by Rex Tyler, who disappeared immediately after.
Back in the flashback, Rip lectures the team about their methods, and then heads to his office to check in with Gideon. Sara follows him to argue on the team's behalf, but as they're talking, a "timequake" happens and they see that someone dropped a nuclear bomb on New York in 1942. The team decides to go to 1942, ignoring Rex Tyler's advice.
Sara talks to Gideon, looking for information on Damien Darhk's whereabouts in 1942. While she's researching, Ray comes to check on Sara, but she sends him away. She leaves, and Stein enters. He and Ray look into the epicenter of the timequake and figure out that just before the attack on New York, Einstein disappeared, and was found dead years later. The war lasted two additional years, and claimed 12 million more lives. They deduce that Einstein must have had something to do with the Nazis acquiring the atomic bomb, and realize that they have to kidnap him before the Nazis can.
Rip asks Jax to stay back during the mission and perform maintenance on the time drive. Jax objects, but eventually relents when Rip reminds him that if they can't stop the nuclear explosion, a fully-functioning time drive is "going to come in handy."
Once they arrive in New York in 1942, the team discusses finding Einstein. They expect him to be at a cocktail party at Columbia. Sara breaks away from the group, followed by Ray, who shrinks down so she can't see him.
At the Columbia party, Stein is surprised and disappointed to see Einstein is kind of a dirty old man. Mick likes it. Rip sees some men dressed as US military, but can recognize by their too-nice clothes that they're fake.
Elsewhere, Sara is waiting in an old warehouse for Darhk to arrive. Ray shows up to prevent her from doing anything dumb, but both of them are surprised to hear that Darhk's contacts are speaking German.
At Columbia, Stein accidentally scatters the women Einstein was flirting with. Mick walks Einstein away.
At the warehouse, Ray and Sara see Darhk selling uranium. Realizing that he's tied up in the plot, Sara is annoyed to realize she can't kill Darhk until she knows what's going on.
At Columbia, Mick and Stein get Einstein to safety in spite of a minor squabble that ends with Stein having to punch out Einstein. Later, in a holding cell on board the Waverider, Stein starts to geek out, but after dropping some references that haven't yet happened in 1942, Einstein realizes that the people he's talking to are time travelers.
The temporal abberation remains unchanged, and Einstein reveals that his ex-wife likely has the knowledge necessary to help the Nazis. As it turns out, Mileva Maric -- Einstein's ex-wife -- has already been kidnapped. Ray can use his suit to track the uranium, though, and bring them to Darhk.
They find the Darhk, the Germans, and Maric just as the baddies are dragging her to a Nazi submarine. Using their powers, they pounce -- but everything goes sideways when Ray's suit can't contain the radiation and disarm the bomb. Things go from bad to worse when Darhk starts to get the upper hand against Sara and the team has to fall back, rescuing Maric but leaving Darhk and the bomb behind. After delivering Einstein and Maric to Einstein's security detail, the group returns to the ship, where Rip is tracking the bomb, and asks Jax to make some last-minute modifications to the time drive, including something called a "time scatter."
Underwater, Darhk launches the atomic bomb at the Waverider, and Rip activates the time scatter, which sends everyone but Rip and Mick into the timestream. Mick, injured in the fight, wouldn't have survived time travel, so Rip puts him in stasis. Rip decides to go down with the ship himself.
In the present day, Oliver bails out of the project, but tells Mick that Nate Heywood as a historian would be ideal to help him find members of the Waverider's crew who have been scattered to the winds of time.
After a little research, Mick and Nate strap in for a trip to 70 million years ago, when Ray Palmer is being chased by a tyrannosaurus rex. The Waverider arrives just in time for Mick to scare the dinosaur off with his gun.
Stein and Jax are in England in 821, where a young prince is about to have them executed for his amusement until the team shows up and rescues them. Sara, of course, is about to be hanged at Salem when the team shows up.
Back at the ship, there's no indication Rip was relocated in time. They call upon Gideon to find him, and she says she can't, but plays his "final" message for them, where he says that he will never abandon hope of seeing them all again some day.0comments
The team collectively agrees to keep working to save the world. They decide that the best way to keep Einstein and Maric safe is for him to publicly acknowledge her contributions to his work in 1942, giving her the perks of security and protection that he's always enjoyed.
On the Nazi sub, the crew turns on Darhk, who isn't interested in helping the Nazis anymore. He says that his partner wants to move onto other things, and when the Nazis tell him that's too bad since his partner isn't here, they're suddenly all killed by a streak of red lightning. The Reverse Flash and Darhk greet one another and smile.