The team's goal is to track down and kill all the mystical creatures that escaped from Mallus's realm and were spread throughout history when the Legends unintentionally released them in order to destroy Mallus.
In an alternate timeline created by Charlie and John Constantine where Nate Heywood, Ray Palmer, and Mick Rory were killed by the Fairy Godmother, the Sirens of Space-Time was formed by Sara Lance, Ava Sharpe, and Gideon. They are presumably the Time Bureau's most capable unit, and led by Hank Heywood who briefs the Sirens daily on their missions. When Charlie wanted to find out what happened to the boys, she transformed into Amaya Jiwe's look and joined the S.O.S, stating that she heard about their magic problem. Gideon, a.k.a. Hard Drive, who was equipped to detect shape-shifter pheromones, discovered "Amaya's" true nature. They were about to kill Charlie, when they were distracted about Sara taking her on alone, letting her escape.
DC's Legends of Tomorrow
- The name also refers to Sara's two alternative sisters who used the codename "Siren" out on the field.
Behind the scenes
- The S.O.S is a reference to the series Charlie's Angels.
- The Sirens' opening sequence is a recreation of the Charlie's Angels theme song.