Dark Return: Belterra, Book 2 (Time After Time)

Dark Return is the sequel to Belterra, Time After Time, and takes place about ten years afterwards. When Belterra was populated long ago by a select group of humans sent here by the ancients in the hope of saving the human race, the indigenous race of bat-like creatures called the Batrach were forced into the ocean and underground sea caves by a giant force field. The force field has now weakened. The Batrach have emerged from their watery prison and they want their planet back.