Marcus Chait

A man willing to kill or die for a diagnosis takes House, Thirteen, and a number of patients hostage in Cuddy's office, where House tries to come up with the correct diagnosis.

When a naval commander is murdered, an old friend contacts Gibbs. His friend, now a senator, believes he's being framed because of his connection with the commander.

The Charmed Ones do not realise that baby Wyatt's new imaginary friend is actually the demon Vicus, who is trying to win Wyatt's trust to convert him to evil.