The Flash gets an assist from XS. Meanwhile, CCPD enlists Chester for help when a mysterious device is found at a crime scene.

With a new speedster in town, The Flash gets much more than he bargained for, meanwhile Cecile's powers experience a growth spurt allowing her to aid Team Flash on an entirely different level.

The Flash and team are in for the fight of their lives, meanwhile, Iris discovers the cause of her time sickness.

With The Flash still reeling from everything that just happened, the rest of the team rallies to support him when he needs it the most.