When a new threat emerges, Dr. Nate Heywood seeks out Oliver Queen to help find the scattered Legends; once reunited, they go to 1942, to keep Albert Einstein from being kidnapped before the Nazis destroy New York City with a nuclear bomb.
While in Nazi-occupied Paris, the Legends find themselves surrounded by the Justice Society of America - AKA JSA - which is threatened by a time aberration; the Legends force their way into the JSA to intercept a mysterious package.
After learning he has powers, Nate accidentally lands Ray and himself in Feudal Japan; Sara, Amaya and Rory agree to find Nate and help him master his powers in order to defend the Japanese village from the Shogun.
The team members travel to 1863, where they find themselves in the middle of the Civil War; Jax and Amaya take on a mission at a slave plantation; Sara feels the burden of being a leader; Ray fights to find his purpose.
A timequake is traced to President Reagan's White House, where Damien Darhk is now a senior adviser; Amaya and Nate break into the JSA; Stein attempts to keep his younger self from creating another time aberration.
In the Old West, the Legends find Jonah Hex in trouble with his arch-nemesis, Quentin Turnbull and his gang; the team realizes they must stop Turnbull from making the West his own lawless territory.
The Legends work with The Flash, Supergirl and Green Arrow to kill the invaders; while working out how to defeat the Dominators, Stein gets distracted by the aberration he created in 1987.
A new time aberration leads the Legends to 1927 Chicago, where they realize they've been set up by Eobard Thawne, Damien Darhk and Malcolm Merlyn; when Stein is taken captive, Sara must choose whether to save him or try to stop the Legion of Doom.
While trying to capture Rip Hunter in 1967, Damien Darhk and Malcolm Merlyn create a huge aberration; Rory requests help from Stein but asks him to keep it a secret from the team.
The legends must find the Spear of Destiny before they can rescue Rip; Malcom Merlyn and Damien Darhk discover that Thawne is trying to pit them against each other.
The Legends find a new time aberration and travel to 1776 to protect George Washington and the American Revolutionary War history; Jax and Stein are forced to step into roles that they don't think they are prepared for.
As the Legends continue their hunt for the Spear of Destiny, they must join forces with the Knights of the Round Table.
Rip forces the Waverider to crash, leaving the Legends stuck 70 million years in the past; Rory suggests entering Rip's mind in an effort to get the "good" Rip back; Nate and Amaya continue to get closer.
When the Legends track Commander Steel to NASA Headquarters in 1970, they discover where Nate's grandfather hid the last fragment of the Spear of Destiny; tension grows between Rip and Sara over leadership of the team.
When the Legends' quest to retrieve the remaining pieces of the Spear of Destiny from the Legion of Doom lands them in France during World War I, they enlist the help of a soldier named John Ronald Reuel Tolkien.
The Legion of Doom rewrites reality, leaving the Legends altered; the reason the Spear of Destiny must be destroyed comes to light.