Later, Luna tells Harry that she and her father believe him about the conspiracy involving Harry, and that they support him. When Harry forms Dumbledore's Army, Luna joins and gets better at defensive magic. When Gryffindor's Quidditch team played against Slytherin, Luna supported Gryffindor by making a life size lion hat that roared. Later in the book, when Harry was going to contact Kreacher about the location of Sirius Black, Luna kept watch for him, telling everyone that there was a gas leak. When Professor Umbridge's Inquisitorial Squad (a group of students who were given power over other students to punish) found him, Luna was captured and held by a Slytherin. While being held, Harry saw her looking out the window, as if she was bored. After they had escaped, it was Luna's idea to travel to the Ministry of Magic by Thestral. During the battle at the Department of Mysteries Luna took an active part in the fighting. After Sirius's death Harry noted that Luna was the only person that could truly comfort him about it, because, like Harry, Luna had also lost someone close to her, her mother.