Hidden within the confines of The Royal Institute of Prehistorical Studies, Sybil is happy enough with her work - and her love life. Then to her dismay, her old adversary, assertive and glamorous Helen Hansen, is appointed Head of Trustees. To add insult, Helen promptly seduces Sybil's boyfriend. Betrayed and broken-hearted, Sybil becomes obsessed with exposing Helen as a fraud, no matter the cost.