In the future — in a world mostly submerged under water — the 19-year-old Sumeragi Aika goes to college while training as an agent by
![[Action] Aika Zero OVA (OVA) (Sub) Full](https://data.animebuu.com/data/23/238/tmdb/poster/1_poster.jpg "[Action] Aika Zero OVA (OVA) (Sub) Full")
In the future — in a world mostly submerged under water — the 19-year-old Sumeragi Aika goes to college while training as an agent by