Attack on Camp Half-Blood(Percabeth, Ereri)
Attack on Titan, Maximum Ride and Heroes of Olympus crossover!
Eren and Armin are flung through a time portal while out on a mission, ending up in America. They are separated on the way, with Armin landing outside Camp Half-Blood, and Eren landing who-knows-where. Meanwhile, Percy and Annabeth have been sent to investigate the time portal by Zeus himself. Though Hermes did deliver the message. Hmm...
Armin meets Percy and Annabeth, and asks them to help him find Eren. They agree, and off they go.
Warnings: monsters, incorrect statements about Contries of the world (I'm Australian, and I've never been to any other country) violence, and science.
And if you're wondering where Maximum Ride went, don't worry. It'll turn up soon enough.