Darth Vader arrives at the Death Star and is greeted by an Imperial Commander. However, Vader informs the commander that the Rebel Alliance has stolen the Death Star plans. The commander then reminds Vader that he does not have the plans for the Death Star and as he doesn't know how to operate the station, he is powerless. Vader then gives the commander the book, citing that it contained a full list of the station's functions and the commander studies it, noticing a glaring vulnerability–in the form of a Thermal Exhaust Port.