The team takes on the case of a man who collapsed while being mugged. When the man complains of new symptoms that do not fit his initial admission profile, the team suspects he is a hypochondriac. As Mr. X continues to fall ill with symptoms unrelated to his neurological disorder, Foreman and the remaining six fellows are assigned to keep watch, and are bemused as they see their own behavioral idiosyncrasies reflected through him. As they attempt to diagnose this human chameleon, they seem to learn more about themselves than their patient, whose true identity is a mystery. Meanwhile, Cameron and Chase keep a running pool on whom House might cut next from the team of candidates, and Foreman engages in a power struggle with House and Cuddy.