哈利波特被困在了姨妈家里，幸亏罗恩及时前来搭救，使哈利在罗恩家愉快地度过了剩余的假期。小精灵多比劝诫并用一切手段阻止哈利回学校，被关在站台外的哈利和罗恩只能私自开飞车回到学校。

传说中的密室被斯莱特林的继承人打开，哈利因为会蛇佬腔被所有人怀疑，哈利发现一本神秘的日记记录了汤姆•里德尔50年前的记忆，随之恐怖袭击事件在原本平静的校园内不断发生。罗恩的妹妹金妮被带到密室，墙上留下了密室的血字警告。霍格沃茨面临被迫关闭的危机。

哈利终于找到密室入口，迎接他的将是可怕的挑战。最终金妮苏醒，伏地魔留下的神秘日记被销毁，哈利挽救了霍格沃茨。

The Dursleys were so mean and hideous that summer that all Harry Potter wanted was to get back to the Hogwarts School for Witchcraft and Wizardry. But just as he's packing his bags, Harry receives a warning from a strange, impish creature named Dobby who says that if Harry Potter returns to Hogwarts, disaster will strike.

And strike it does. For in Harry's second year at Hogwarts, fresh torments and horrors arise, including an outrageously stuck-up new professor, Gilderoy Lockhart, a spirit named Moaning Myrtle who haunts the girls' bathroom, and the unwanted attentions of Ron Weasley's younger sister, Ginny.

But each of these seem minor annoyances when the real trouble begins, and someone - or something - starts turning Hogwarts students to stone. Could it be Draco Malfoy, a more poisonous rival than ever? Could it possibly be Hagrid, whose mysterious past is finally told? Or could it be the one everyone at Hogwarts most suspects... Harry Potter himself!