Without a Trace Episode 3.03 Light Years

Teddy Coda, an x-ray technician with a fascination with alien lifeforms goes missing. After speaking to members of Teddy's friends and family, the team learn that his memory has been clouded by his alien obsession and that events in his childhood have been muddled. With Jack back in charge the team must decipher fact from fiction in order to track down Teddy before it's too late.