Watch This Boy Can Fight Aliens Online

*The Second OVA of Kono Dan series. They say look before you leap and make sure you can swim before you go in the deep water, but when a picture of his late grandfather falls into the ocean, Shima jumps in after it without thinking. Nearly drowning as a result, he is instead saved by a very perfect stranger... one whose strangeness extends to only being human from the waist up! For Shima, who's always felt like a fish out of water himself, it's more than just a revelation, and the young man and merman quickly begin to bond in ways neither anticipated. And yet, it's going to be far from easy sailing. After all, Shima and Isaki aren't just from opposite sides of the tracks, they're from entirely divergent species, and swimming in separate gene pools may make maintaining a long term relationship a whole different kettle of fish!

When aliens suddenly invade the world, Earth seems to be fighting a losing battle until Arikawa, one of the defense command staff, accidentally discovers a young man lying on a hill. Tests soon prove the impossible: this one teenager, Kakashi, has the power to defeat the attackers! Unfortunately, Kakashi has also lost his memory, and with it the knowledge of how to actually use his power. Moving Kakashi in with himself and his own commander, Shiro, Arikawa accidentally starts a strange triangle of emotions and relationships. A triangle that threatens the fate of the planet as Kakashi begins to question his own motivations!