In this fifth installment to The Uncaged Series, Serenity and Sky tackle life together as new parents to their toddler twins. Joined by Blackbird and her daughter, Sky and Serenity feel safe in the Sanctuary. But their peace is shattered when the twins are abducted by a woman named Haven, Director of a new Museum called The Aquarium -- a sea-scraper hundreds of miles deep in the ocean. With their children's fate in the balance, Serenity and Sky agree to a two-year contract as a dual interaction in The Aquarium, re-introducing Serenity to the crowds as the Sea Star. But navigating the perils of this new Museum will be more dangerous than ever. The Director has a reputation as the country's most notorious assassin, her predatory brother has made Serenity his favorite new target, and the performances demanded of Sky and Serenity are simply unimaginable. When history starts to repeat itself--this time with female bodies showing up strangled--Serenity realizes that there's no one left to help her. But will saving herself cost her more than she can bear?