Seastalker

The player's character is a young inventor and marine scientist. A research facility called the Aquadome issues a call for help, indicating that the undersea structure is being attacked by a sea monster. With helpful assistant Tip, the player must navigate to the Aquadome in the new untested two-person submarine Scimitar and investigate the problem. But that isn't all... it looks like there may be a saboteur within the Aquadome as well.