With Rikki departed from the café, Zane hires Sophie to replace her as manager and she immediately asserts her new authority - changing staff as well as the decor of the café. Kim gets a job in the new regime which she relishes and begins to mimic her mentor, Sophie, at work and home, driving Cleo mad. Sophie's changes coincide with an allergic reaction in Bella that sets her mermaid powers off involuntarily and inhibits her singing in the band. Will and Rikki attempt to solve the mysterious cause of Bella's unusual ailment while Sophie threatens to replace the band in the café if Bella can't perform. Meanwhile, Cleo's encouraged to step in for Bella as lead singer under Nate's keen tutorage. Rikki finds the surprise solution to Bella's problem and confronts the uneasy situation with Zane and Sophie - reclaiming her freedom to attend the café and return for the band's big gig.