Lissie's in a difficult situation. She's gone to stay with her step-family for a fortnight, and her spoilt-brat half-sister is doing all she can to make Lissie's life as unhappy as possible. Lissie even thinks she's wrecked her precious cello. But the wicked step-sister knows how to turn on the charm for everyone else - and Lissie's mum thinks she's adorable. She won't hear a word against her, and thinks Lissie is just making trouble. How can Lissie make her see what's really going on?