Power Rangers Operation Overdrive Episode 21 Once a Ranger, Part II Episode Title:Once a Ranger, Part II.Episode Description:No longer having Ranger powers, the former Overdrive Rangers return to their civilian lives. All but Mack, who learns of Thrax's plans to destroy the Sentinel Knight, seeks out the only item capable of doing so, the legendary sword Excelsior. Meanwhile, their replacements, the team of Returning Rangers, head to Angel Grove to seek out the only being capable of repairing the Morphing Grid: Alpha 6.