Oona is acting strange, well stranger than usually. She's not confiding in anyone and is getting farther and farther away from her friends. When the Irregulars learn that she moved in with her criminal father things go from bad to worse. With more trouble being caused in Shadow City the girls need Oona's friendship more than ever, but maybe it's not all Oona's fault... The girls must join as one and work together to fix all their problems, but can they do it before it's too late?