Gargantia on the Verdurous Planet

Season 1, Episode 7: A Soldier's Fate

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When Ledo has an encounter with a whalesquid undersea, he attacks and kills it because of its similar appearance to the Hideauze. Little did he know that whalesquid are considered sacred, so murdering one is taboo, and soon the whole ship is in an uproar over it. Ledo, however, believes that whalesquid are Hideauze and he's determined to carry out his mission by slaughtering more of them before they decide to target humans on Earth. Just as Amy tries to stop Ledo, a huge pod of whalesquid approaches the fleet...