Ep. 50: The group visits Gaito's castle to thwart his world domination scheme and save Noel and Coco.
Aired on March 13, 2004

50
Lucia, Hanon, Rina, and Caren travel to Gaito's castle with the dual objectives of stopping his plans for world domination and rescuing their friends, Noel and Coco. Coco, identified as one of the mermaid princesses of the South Pacific, pleads with Sara to return to her former self. Simultaneously, Lucia faces an internal struggle, forcing her to confront and challenge her own heart during this mission. The narrative focuses on the group's efforts to intervene against Gaito while addressing the personal transformations required of Sara and Lucia amidst the rescue operation.
Episodes
- Ep. 46 · Kaito Confesses to Lucia on the Beach During Sunset
- Ep. 47 · Gaito visits Kaito in a dream while Sara gives Taro a key to the castle
- Ep. 48 · Kaito experiences a strange dream where Gaito reveals their brotherhood and Pantharassa clan heritage.
- Ep. 49 · Sheshe and Mimi steal mermaid pearls to power evil microphones.
- Ep. 50 · The group visits Gaito's castle to thwart his world domination scheme and save Noel and Coco.
- Ep. 51 · Mermaid Princesses confront Gaito, Kaito, and a hypnotized Taro in a battle against one of their own.
- Ep. 52 · Kaito learns Lucia's identity as Mermaid Princesses summon Aqua Regina to defeat Gaito.