Jason Blood leaves town while a creature called the Howler is on the loose. The Howler attempts to put his possession on Jason Blood, but cannot, Merlin explains, because he is already possessed by Etrigan.
An anthropoligst named Eric Schiller follows Blood onto a plane and explains his situation. Jason offers to exorcise the Howler from him, but Glenda comes in and stops him, causing the Howler to emerge and go on the attack.
Ultimately, the Howler is sent out the window, leaving Schiller for dead.