Over a torrent sea - Christopher L. Bennett

As the Federation recovers from the devastating events of Star Trek: Destiny, Captain William Riker and the crew of the USS Titanare ordered to resume their deep-space exploration. But even far from home on a mission of hope, they cannot escape the scars of the recent cataclysm.

Painfully trying to rebuild their lives, they encounter a planet made almost entirely of water, which Aili Lavena, Titan's aquatic navigator, sets out to chart. But when their good intentions bring calamity to this new world, Lavena and Captain Riker are cut off from the Titan and feared lost. Deanna Troi is left to face a life-changing event without Riker, while the rest of the crew must brave the crushing pressures of the deep ocean to undo the global chaos they have triggered. Stranded with her injured captain, Lavena must win the trust of the beings who control their fate -- but the price for Riker's survivial may be the loss of everything he holds dear.