When Barry Allen and Oliver Queen wake up one morning and realize they have swapped bodies with each other, the two set off to find out what disturbed the timeline to cause such a shift. However, things quickly go from bad to worse when they present their case to Team Flash and the gang doesn’t believe them. Barry and Oliver realize they need Supergirl’s help and travel to Smallville on Earth-38 where they end up meeting Kara’s cousin, Clark Kent, and intrepid reporter, Lois Lane. In Part 2, Oliver and Barry get a lead on John Deegan and head to Gotham City with Supergirl to figure out why their reality has changed. While there, they meet the mysterious Kate Kane aka Batwoman who provides them with information that leads the group to Arkham Asylum. In Part 3, the epic Elseworlds Crossover comes to an end as Supergirl, The Flash, Green Arrow and Superman engage in the battle of their lives.