Stacy has a spa day planned for herself and Candace, but they get side tracked when Jeremy is participating in a house-building program for the homeless and Candace joins as well in hopes of impressing him. Fortunately, the girls are able to get their spa day after all when Phineas and Ferb build their own spa with its own special features. Meanwhile, Doofenshmritz finds a cat which causes a lot of problems when he's trying to carry out his latest evil plot.