A time agent, played by Arthur Darvill (Rory from Doctor Who) collects a bunch of supporting characters from Arrow and The Flash to help him save the future and shenanigans ensue because they have no idea what they are doing and argue a lot but also try to save people and each other and keep screwing up the future and then having to try and fix it again.
I'm only about seven episodes in but it's entertaining and full of pop culture references and in jokes. My faves are Rory and Snart - criminal partners who've been inseparable since they met in juvie when they were 14 years old. They're played by Dominic Purcell and Wentworth Miller who played brothers in Prison Break. One time Rory is in a Soviet prison and the others are plotting to break him out and Snart is like 'this isn't my first prison break'.