The comedy is pure reference velocity, Lovecraft, tokusatsu, dating sims, whatever, fired at you so fast that even if one joke whiffs, three more land while you're still laughing. Mahiro's exhausted deadpan as cosmic horrors treat him like a side character in his own harem is the only tone that could survive this much chaos. The show doesn't care if you get every reference because it's funny enough on the surface, sharp enough underneath, and self-aware enough to never overstay its welcome in twelve episodes.

Mahiro Yasaka is an ordinary high school student until a monster attacks him out of nowhere. His rescuer is Nyaruko, a silver-haired girl who says she is the shape-shifting deity Nyarlathotep from Lovecraft's Cthulhu Mythos, dispatched to Earth by the Space Defense Agency. The creature, she explains, was a Nightgaunt that meant to kidnap him and sell him into slavery. Nyaruko promptly falls head over heels for Mahiro and moves into his home, much to his annoyance. Soon Cthuko, who is fixated on Nyaruko, and Hasuta, a boy often taken for a pretty girl, join them. As Great Ones from the mythos keep arriving on Earth, the three aliens guard Mahiro from threats to him and the planet while turning his days upside down, though all he wants is peace. The result is a sci-fi romantic comedy that plays Lovecraftian horror for laughs.