8.30PM WEDNESDAY / JULY 2

Melinda, (guest star Michelle Trachtenberg), is a teenage girl who is confined to a 'clean room' by her mother after a heart transplant. Her mother is determined to ensure that her daughter does not come in to touch with any life-threatening bacteria or substances that could cause her an allergic reaction. However, Melinda's mother doesn't foresee a sexual interaction between Melinda and her boyfriend, which results in Melinda going in to anaphylactic shock.

When House and his team discover the truth about Melinda's sexual encounter, they think they have worked out the cause and the solution to her shock. But when she develops congestive heart failure, they realise they have a lot more work on their hands. As her heart condition worsens, Melinda develops a paralysis that is slowly working its way towards her heart – it is a race against time to stop the paralysis and prevent Melinda from dying.

Quote from this week's episode:
House: Everything sucks. Might as well find something to smile about.

Trivia about guest star Michelle Trachtenberg:
Michelle Trachtenberg has had a long and diverse career in both television and film, considering being only 22 years old. Best known for playing Dawn Summers in 'Buffy the Vampire Slayer', Michelle has also starred in movies 'Inspector Gadget', 'Harriet the Spy', as well as 'Six Feet Under', 'Law and Order: CI', and 'Gossip Girl'.