A family of insane people decide to spend their summer vacation SCUBA diving around sunken Dutch slave ships and take a few souvenirs with them -- including a mystery disease daughter Julie catches when the sealed glass jar full of scabs she brings to the surface breaks and cuts her hand. Idiot. House is sure it's smallpox until the CDC shows up, shuts PPTH down, and quarantines Julie and the rest of her possibly exposed family. This makes it impossible for House to run tests on Julie to prove that it isn't smallpox, especially after Julie's stepfather comes down with smallpox symptoms of his own. House thinks it's just the man's compromised immune system due to a recurrence of kidney cancer that's causing him to react to the smallpox vaccine the family was given earlier, and he's so sure that he breaks into stepdad's room to inject him with interferon and prove it. Except the stepdad doesn't get better. In fact, he totally dies. And now House is stuck in the quarantine room and possibly exposed to what the CDC is more sure than ever is smallpox. Fortunately, Martha M. Masters hasn't been fired again yet and so is able to combine her knowledge of medicine and history (along with the help of a Dutch webcam performer-turned-translator) to come up with the correct diagnosis of the smallpox-like rickettsialpox in time to save Julie, whose stepbrother has got to be just a little bit angry at her for killing his dad. House is also saved, but his near-near-death experience isn't enough to earn Cuddy's forgiveness for lying to her last week. Also, Wilson and his ex-wife/girlfriend's inability to handle a kid with cancer makes them want to be parents for some reason.