Prologue: The Flash

The Flash faces a tough decision: save Star City and lose Iris' confidence or let Slade Wilson return to kill everyone in Star City and keep his good status with Iris and his friends.

Meanwhile, Green Arrow has taken a break from being a vigilante to be a father to William. The team is still on but without their leader it is chaos.

There is only one way to save Star City: open up another breach inside S.T.A.R. Labs and travel to Star City to find Green Arrow and convince him to travel to another Earth to save his city.