Where does Nat wake up? What's changed?

Nat wakes up in a different bed, wearing different clothes than the night before. He is greeted by a boy named Harry who seems to know who Nat is, but who Nat has never met before. Nat does not recognize anything around him, but no longer feels ill. Harry remarks that he feared Nat had been suffering from the plague. He explains to the confused Nat that he is a student at St. Paul's School and is on loan to William Shakespeare's company for the week.