S1·E3 The Third Senshi is Rei-chan the Priestess
Aired October 18, 2003
Synopsis
During a string of disappearances of miko priestesses, Usagi runs into one of them, Rei Hino, who is the prime suspect of the missing girls. Usagi defends her reputation, until the two got pulled into another dimension by a Youma, causing Rei to awaken as Sailor Mars.