This is a brief review of last night’s episode of The Flash that is part of a four-night crossover event on the CW featuring Supergirl, The Flash, Arrow, and The Legends of Tomorrow. I will have a full review of the crossover week after it concludes on Thursday so be sure to check back for more. The CW’s Arrowverse crossover week kicked off on Monday with a new episode of Supergirl. However, this week was...