Sailor Moon (TV Series 1995–2000) 1x22

Naru is still very depressed after Nephrite's death. Usagi and Umino decide to take her to Yokohama to cheer her up. There, a kindly priest is attacked by Zoisite. Mamoru realizes that he is Tuxedo Mask, and drops a locket on the ground, where Usagi finds it.