Aoki Ao no Atopos

A surveillance ship belonging to the company Ferret disappeared for a period before being discovered, but all 115 people on board were nowhere to be found, with no evidence of their presence remaining. Masato, whose sister works for Ferret, is sent to deliver supplies for an investigation into the ship, which has returned empty. At the company, he meets Uto, a girl who also has a missing sibling who worked for Ferret and was last seen on the ship. Together, Masato and Uto set out to uncover the secrets of the mysterious island where the missing crew is believed to have been left behind.