Pale Cocoon

A future where the continuity of history has broken off, a world of enormous ruins that continues endlessly. Oceans and continents have vanished, existing only within the archives brought up from the remains. Ura works in the Archive Excavation Department, which restores and analyzes the data left behind. One day, he finds a disturbing visual record... (Source: Anime News Network)

Agent Aika

A catastrophic earthquake has left Tokyo, and most of the Earth for that matter, under the sea. Aika is a salvager who retrieves various remains from the watery ruins. When Aika accepts the dangerous mission of locating and obtaining the mysterious Lagu, she discovers that she's not the only one after it.