Episode 461: The Missing Page
Scenario: The Detective Boys are doing a book report when Ayumi notices that the last page to her book, Alec's Adventure, has been torn off. Conan and Ayumi decide to search for Tsukasa Naito, the one who burrowed out the book last. The Detective Boys later discover that a valuable stone, the Sairai Seki (再来石, lit. Return Stone) was stolen. Conan realizes that Tsukasa must have stolen the stone believing it is the same stone from Alec's Adventure, Futabi no Ishi (再びの石, lit. Again Stone), due to the same kanji and wants to use it to regain a lost object. The Detective Boy's investigate Tsukasa's house and discovers a piece of the torn page confirming Conan's suspicion.
They find a picture of Tsukasa and his mother at the beach and a coded message behind the photo deduced to be the location of the beach. The Detective Boys follow the clues and arrive at the beach where they find Tsukasa attempting to use the stone to resurrect his dead mother. Tsukasa's father arrives and hugs him making him realize his mother is gone for good. Later that evening, the Detective Boys and Tsukasa returns the stone to the school.