is the 100th episode of The Flash , originally airing on December 4, 2018. It serves as a commemorative milestone that balances a trip down memory lane with the urgent need to defeat the season’s "Big Bad," Cicada. Critical Consensus
: Includes guest stars Michelle Harrison, John Wesley Shipp, and Teddy Sears. [S5E8] What's Past is Prologue
: Critics from Culturefly and IGN highlighted Tom Cavanagh’s performance as Eobard Thawne, particularly in the tense scenes with Nora, as a major standout. is the 100th episode of The Flash ,