Departure (2019)

S4E19 Petty in Pink

Serena recruits Charlie to go incognito, Gossip Girl-style, to uncover the reason behind Dan and Blair's frequent meetings, as well as the influence of a surprising newcomer in their lives. Meanwhile, with Nate by her side, Raina embarks on a quest to find her estranged mother. Chuck, on the other hand, faces disappointment when shocking details from his past come to light, shattering his aspirations for his legacy.