Moment From Harry Potter and the Order of the Phoenix

Bellatrix kills Sirius
During the battle at the Ministry of Magic, Bellatrix catches Sirius Black by surprise and kills her cousin and Harry’s Godfather.
Returning for his fifth year of study at Hogwarts, Harry is stunned to find that his warnings about the return of Lord Voldemort have been ignored. Left with no choice, Harry takes matters into his own hands, training a small group of students – dubbed 'Dumbledore's Army' – to defend themselves against the dark arts.
Tags: prophecy, witch, loss of loved one, magic, child hero, dying and death, school of witchcraft, black magic, sorcery, supernatural, occult, mystical land, based on young adult novel