1x11 - Nanana's Buried Treasure

Isshin's plan has rendered Ikusaba's "Shadowfins" useless, and victory is right before the Adventure Club's eyes... but then Ikusaba unleashes the power of his other Nanana's Collection treasure, leaving Juugo in serious trouble. Then Tensai steps in, telling Ikusaba she's figured out his power and offering him a proposal.