In "Harry Potter and the Half-Blood Prince," Harry confronts Snape about his loyalty to Voldemort and questions his actions throughout the years. Snape reveals that he has been spying on Dumbledore and the Order of the Phoenix for Voldemort, but also explains that he has been able to pass on valuable information to Dumbledore. Narcissa, Draco's mother, asks Snape for help in protecting her son, and Snape agrees to make an Unbreakable Vow to assist Draco if necessary. Dumbledore reveals that Sirius left everything to Harry in his will, including the house at Grimmauld Place. Harry also learns more about Voldemort's past and his connection to the Gaunt family. The book ends with Dumbledore showing Harry two important memories.