Case Closed - Season 1 Episode 898 The Melting Cake!
Overview: When Conan, Kogoro, and Ran go to Cafe Poirot in the morning, they discover the special cakes Amuro Toru put in the mini fridge have melted. It has apparently happened several times before, but the cause is unknown. Later, Mitsuhiko, Genta, and Ayumi arrive at Poirot. Azusa hires a professional to fix the fridge, but it's not broken. Genta reasons the owner of a rival bakery must be destroying the cakes during the night. Conan believes Genta's theory is wrong, but sets up a camera outside the store to film the interior of the shop after closing anyway.