A Man's Promise! Luffy and the Whale Vow to Meet Again

Crocus recounts how Laboon arrived half a century ago alongside the Rumbar Pirates, a young whale that trailed the crew out of West Blue rather than stay behind. The pirates regarded the animal as family and, before braving the Grand Line, left it with Crocus and swore to return within three years. The doctor admits he has tended Laboon's self-inflicted wounds from inside the beast ever since. Luffy tries to recruit Crocus as the Straw Hats' physician, but the aging man declines.

Once freed from the whale's belly, the crew debates whether the Rumbar Pirates ever survived. Crocus believes they fled the Grand Line and broke their word, yet he refuses to abandon Laboon over a bond he formed long ago. Moved to act, Luffy snaps the Going Merry's mast and clobbers the whale with it. After a brief brawl, he calls the match a draw, names Laboon his rival, and paints the crew's skull mark on its hide so the creature has a future fight to anticipate.

Miss Wednesday and Mr. 9 slip off the ship but lose their Log Pose, which Luffy recovers, and the pair are then bombed by the Unluckies. Nami discovers that mineral magnetism renders normal navigation useless here, so Crocus explains the Log Pose locks onto each island's field and ultimately guides travelers toward Laugh Tale, the place only Gol D. Roger reached. With Laboon hauling the stragglers from the sea, the crew agrees to ferry Mr. 9 and Miss Wednesday home, setting course for Whisky Peak.

Crocus reveals Laboon's origin with the Rumbar Pirates and his role as the whale's caretaker and doctor. Luffy battles Laboon to a standstill, declares it his rival, and marks it with a Jolly Roger as a promise to return. Mr. 9 and Miss Wednesday drop their Log Pose, which Luffy claims, and the Unluckies bomb the duo. Nami and Crocus explain Grand Line navigation through the Log Pose, naming Laugh Tale as Roger's destination. The crew departs for Whisky Peak with the two strangers aboard.

This episode closes out the Reverse Mountain Arc and debuts Yorki, Mr. 13, and Miss Friday. It marks Luffy's first use of the technique Gomu Gomu no Ikebana. It was the final episode aired on a Wednesday before the broadcast slot moved, and the last to use RUN! RUN! RUN! as its ending theme. A minor change from the source manga has Sanji kicking Luffy in the stomach rather than the face after the captain devours all the food. A spelling error appears at the fifteen-minute mark.