"Case Closed: The Last Magician of the Century" is a feature-length anime film based on the popular detective series "Case Closed" (also known as "Detective Conan"). The story revolves around a mysterious heist involving a legendary jewel known as the "Phantom Lady's Tear," which is stolen during a high-profile magic show in Tokyo. The theft is orchestrated by a group of international thieves known as the "Phantom Thieves," who are notorious for their elaborate heists and ability to evade capture.

The protagonist, Shinichi Kudo, a brilliant high school detective trapped in the body of a child under the alias Conan Edogawa, becomes involved in the case when the Phantom Thieves announce their next target: a priceless artifact tied to the legacy of the 19th-century magician, Kaitou Kid. The artifact, a clock tower with a hidden mechanism, is said to hold the key to a long-lost treasure. Conan, along with his friends and allies, including Ran Mouri and Inspector Megure, must unravel the clues left by the thieves while navigating a web of deception and misdirection.

Kaitou Kid, a master thief and recurring character in the series, plays a central role in the story. Known for his flamboyant heists and uncanny ability to mimic others, Kid becomes both an adversary and an unlikely ally to Conan. The narrative explores the rivalry and mutual respect between the two, as they race against time to uncover the truth behind the Phantom Lady's Tear and the treasure it is connected to. The film is filled with intricate puzzles, high-stakes action, and dramatic confrontations, culminating in a climactic showdown at the clock tower.

The story delves into themes of illusion, legacy, and the blurred line between justice and crime. It also provides insight into the motivations of the Phantom Thieves and their connection to the historical figure of Kaitou Kid. The film maintains the series' signature blend of mystery, suspense, and character-driven drama, offering a self-contained yet engaging narrative that appeals to both longtime fans and newcomers.