“Worlds lived, worlds died. Nothing will ever be the same.”

The crossover starts on Supergirl S05E09 Crisis on Infinite Earths: Part One (I), Batwoman S01E09 Crisis on Infinite Earths: Part Two (II), The Flash S06E09 Crisis on Infinite Earths: Part Three (III) and Arrow S08E08 Crisis on Infinite Earths: Part Four (IV)

Sara, Ray and Mick are shocked to discover that the Legends have become famous. The Legends discover that their new problem is Rasputin. Constantine thinks he knows the reason for new time blips and informs the team that it won't be easy to defeat.

When a new blip lands the Legends in 1947 Los Angeles, it puts them on the trail of Benjamin “Bugsy” Siegel who seems to take pleasure in fraternizing with Hollywood Elite. Sara, Ray and Constantine devise a plan to capture him while Ava and Rory sit on the sidelines for the time being. They soon realize that they need to worry less about Bugsy and more about his girlfriend. Ava is struggling with being on the sidelines with Rory. Meanwhile, Nate accompanies Behrad to his dad’s birthday, where Nate meets Behrad’s sister, Zari, who seems familiar to him.

When the Legends discover a new Encore, Sara, Rory and Ava end up crashing a high school reunion to attempt to stop a serial killer from finishing unfinished business. The Legends devise a plan to send Nate, Ray, Nora, Behrad and their hostage Zari, back in time to try and intervene in order to try to save everyone including them. Meanwhile, Constantine is annoyed that Charlie has been squatting in his old home, but it might be the blessing in disguise they were not looking for.

When Sara is called away on business, she leaves Ava in charge and Ava tries to impress the team as they try to take on their latest Encore, Marie Antionette. With Zari still on the ship, Behrad convinces the team to bring her along on the mission which they all hope isn’t a mistake. Meanwhile, Constantine finally confronts someone from his past with the help of Charlie, which leads him on a journey through his past.

With Sara still away from the Waverider, the Legends find a new Encore with Ava’s new invention, the Prognosticator, and must now try to defeat Genghis Khan in 1990s Hong Kong. Constantine’s life is hanging in the balance, and Ray, Nora and Gary all try to help him, but Constantine tries to make a deal with Astra instead. Meanwhile, Behrad has been confused about Charlie’s recent behavior, but they all learn why Charlie is trying to out run her past and from what

Ray plans a date night for him and Nora, but all goes awry when an Encore shows up making the team think on their feet and create a lie to keep the Encore at bay. While trying to fool the Encore, Ava learns what Sara was really doing while she was away and confronts her. Charlie and Constantine make a deal to work together, which will benefit both of them. Meanwhile, Rory is upset when he gets negative comments about his book, so Zari helps track down who the critic is, and Rory gets more than he bargained for.

The Legends continue their hunt for pieces of the Loom of Fate and find themselves face to face with William Shakespeare. Ray, Nate, Rory, Constantine, Charlie and Behrad stay a little longer on the mission making things worse after lying to Sara. Meanwhile, Ray and Nora make another big life decision that leaves the team surprised and best buds, Nate and Ray, on the outs.

Sara, Constantine and Charlie find themselves in British Columbia searching for another piece of the Loom, but they run into a problem they couldn’t have foreseen. Zari has been having trouble feeling like herself, so she goes on meditative journey at the suggestion of Behrad. Meanwhile, Ava volunteers to try and help Rory with a personal problem.

With Sara recuperating from her latest battle, Charlie starts to notice something might not be right with her. Still searching for the Loom, Constantine and Zari find themselves trapped in a 1910 boarding house with a slew of out-of-time Encores. Meanwhile, Ava, Gary and Rory take a trip while Nate and Charlie hold down the Waverider.

Everyone is eager to use the Loom of Fate, but the team must decide who they want to bring back first leaving Charlie to make a tough choice. Sara struggles to understand what has happened to her and with the help of Constantine and Ava, they try to figure out how to help her. Meanwhile, Rory has a guest on the ship that he is trying to impress.

The Legends find themselves going back to college and form a sorority in order to try to retrieve an ancient artifact called the Chalice of Dionyus that will help Charlie operate the Loom of Fate. Proud to be back at his college, Nate falls under Dion’s spell, letting him know of Sara, Astra, Ava and Charlie’s plan to get the cup. Meanwhile, on a father-daughter weekend, Rory takes Lita on a college tour, but Rory bails on Lita for an unexpected reason.

After drinking from Chalice, the Legends have immortality for 24 hours, which gives them time get to the Waverider and use the Loom of Fate. However, they quickly discover that the sisters have stolen the Waverider and they are stuck at Constantine’s house in the middle of nowhere in London during a Zombie Apocalypse. Meanwhile, Gary is left on the ship and once he discovers what is going on, he takes something important to the sisters.

After Charlie does the one thing that goes against her nature when it comes to her sisters, she tries to protect the Legends by scattering them in different television shows. Of course, in true Legends style some can’t just be blissfully ignorant and happy but figure out a way to end up messing with the system.

Still controlled by the Fates, the Legends find themselves in 1984-esque world, they soon discover that things aren't as they thought they would be. The Legends must convince the civilians to trust them and stand up for their right to choose, but the Fates don't make it easy by resurrecting the Encores once again.

After a night of celebrating their beating the Fates, the Legends quickly discover that Sara is missing. Ava sends Rory and Behrad to follow a lead on who can possibly help them find Sara, while Constantine tries to work his magic. Meanwhile, Sara does all she can to try to escape but is shocked to learn who one of her kidnappers turns out to be.

The Legends find themselves tracking an Alien in 1950s San Bernadino and having to figure out what is making the town go on a feeding frenzy. Meanwhile, after crash landing, Sara tries to figure out a plan and runs into none other than Amelia Earhart.

The Legends find themselves in 2045 trying to defeat an Alien warrior which leaves Zari no choice but to enter a popular singing competition. Sara finds herself struggling after being attacked but someone familiar helps her to keep searching for refuge. Meanwhile, Zari and Constantine have a much-needed conversation with each other.

The Legends are shocked when Rory takes command and manages to find the location of an important Alien, but he also lands them in the middle of the Cuban Missile Crisis. The team makes the decision to split up, leaving Nate and Zari to work together to stop a nuclear disaster alongside JFK while Behrad tries to leverage his newfound friendship to stop Castro from starting a war. Meanwhile, with Spooner's help, Rory makes an unlikely deal that could lead him on a solo mission to find Sara.

With Astra now a mortal, she finds it hard to adapt to the real world with no guidance from Constantine. Frustrated and lonely, Astra makes a new friend who promises to help her, but her eagerness for the easy way out could have some real repercussions for those closest to her. Meanwhile, Sara meets the person responsible for her kidnapping and tries to convince others to help her escape.

Mick takes the Waverider and Kayla to try and find Sara, but these enemies find themselves needing each other to survive after landing on the possible planet Sara is being held captive. After a report of an Alien attack, the Legends return to their new headquarters where both Spooner and Astra try to connect to the Alien. Meanwhile, Sara devises a plan to escape by using her charm to win over Bishop.

With Ava a wreck, the Legends make a last-ditch effort to keep Sara from being abducted in the first place, even knowing that it will alter the timeline. Sara grapples with a discovery about herself and is shocked when Rory finds her on the mystery planet. Meanwhile, Spooner envisions what her life would be like if she hadn't joined the Legends.

With everyone finally back together, the Legends find themselves looking to Nate to keep everything calm while in the old West on a mission to find an alien. After trying to keep things normal, Sara reveals her secret to Ava and the team, leaving them all shocked. Constantine looks to Gary who might have the answer to his problem. Spooner and Astra are forced to work together despite their clashing personalities which ultimately helps push them to hone their powers.

Behrad is disappointed because the Legends have forgotten his birthday. Meanwhile, Rory's behavior has been a little off, so Sara and Gary become determined to find out what happened, but Rory gets some unexpected news from his daughter, Lita.

With Constantine obsessed with getting his powers back, he convinces Spooner to join him on the quest to find the Fountain of Imperium. After they find themselves at the end of the Spanish Civil War, Spooner makes an unexpected bond with someone she feels the need to protect. Meanwhile, Sara and Lita are concerned about Rory's health, so they try to convince him to take it seriously.

When the Legends track down another Alien pod, they find a device that transports them to a cosmic bowling alley. Spooner makes a bet against the reigning champs for a ride back to the Waverider, but not everyone is happy about the plan when they realize what they are up against. Elsewhere, Nate plans a romantic date for him and Zari, but nothing goes as planned. Meanwhile, Behrad and Gary try to distract Ava from what's going on with wedding planning.

The Legends are ready to get back home, but after Constantine overloaded Gideon, they are going to have to go the old fashion way to preserve the ships energy. Trying to entertain themselves, tensions start to grow high, so Gary suggests playing a murder mystery game to pass the time. Meanwhile, Rory and Gary deal with an unexpected guest that arrives on the Waverider.

With the Legends on high alert with their unwanted guest in their custody, Ava is tasked with the interrogation while Nate and Sara watch. Rory is struggling with the terrible pain in his head and Gary tries to help to manage it the best he can. Meanwhile, Zari enlists Astra and Spooner's help to figure what is going on with Constantine.

When Astra and Spooner find themselves as stowaways, they learn that Constantine is still chasing the Fountain of Imperium and find themselves in 1920s Texas. With the rest of the Legends stranded, they come up with a plan to get help by using Rory as bait that will also help reunite him with something that is special to him. Meanwhile, Spooner learns some information about her past that she wasn't expecting.

When Sara realizes Bishop's plan, Ava convinces Sara to allow the Legends to make exception to the rules to help fight back. Behrad comes up with an interesting plan, that allows Sara to connect with an old friend. Meanwhile, amidst a battle Sara and Ava make an important decision but need the help of the team to pull it off.