As we discussed last week (and earlier promos made obvious), Olivia Wilde returns as Thirteen when House comes back from hiatus next Monday, April 11.

Thirteen's hiatus wasn't sweeps-related. She did a six-month stint in the BIG house. But why was the ailing underling sent to jail in the first place? Unclear.

This clip from "The Dig" (the show's 150th episode) offers a major clue to that mystery, however. Watch it below and see if it's what you expected ...

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.