Ao no Exorcist

Synopsis

Rin, Izumo and Renzo are sent for their first mission as Exwires to a coast town, chaperoned by Tsubaki. While Rin and Renzo fails to sell fried squid, Izumo goes out in the ocean, but gets a leg cramp, alerting a boy named Yohei to rescue her from supposedly drowning, though accidentally bumping her head in the process. It is foretold that the coast town has been afflicted by the presence of a kraken. Later that night, the three go with Yohei to the pet store for supplies. Yohei reveals his father set out to face the kraken six months before and is still missing. The boy plans to enact his revenge against the creature as he believes it killed his father. After Tsubaki leaves for the night, Yohei visits Izumo to give her ointment for her head. The next day, Rin, Izumo and Renzo monitor Yohei all day to keep him from going into the ocean. Come sunset, the kraken appears and attacks. As the three are not able to defend themselves, Yohei sets out by motorboat and shoots the kraken with a harpoon, only to be thrown into the ocean. Rin, after saving Yohei from drowing, prepares to use his demonic powers, but Yohei's father is shown to still be alive, much to Yohei's surprise.

(Source: Wikipedia)