Agatha, in her late thirties, from a poor background and working as a temporary employee in a supermarket, knows exactly what her perfect life looks like. It is the life of someone else: that of the attractive Meghan, the wife of a successful television presenter, who takes care of her two children in their London townhouse. Meghan walks past Agatha every day without a greeting, oblivious to her longing glances. Yet, the two women share more than they realize. Both have dark secrets, and envy and violence lurk in their lives. And when Agatha decides she no longer wants to just watch, everything spirals completely out of control...