"Scooby-Doo! and the Samurai Sword is the thirteenth of a series of direct-to-video animated films based upon the Scooby-Doo Saturday morning cartoons. It, along with The Goblin King, was produced and completed in 2008, but Goblin King was released first for the Halloween season. It was released on April 7, 2009, and it was produced by Warner Bros. Animation, though it featured a logo for and copyright to Hanna-Barbera at the end (This was the last time the logo was shown). It features the Mystery, Inc. gang traveling to Japan and is the final Scooby-Doo film to have Casey Kasem as the voice of Shaggy, as he retired a few months after the film was released."
At a Tokyo museum of ancient history, Mr. Takagawa, the curator, and Kenji, a janitor, witness the resurrection of The Black Samurai, an ancient Japanese warrior whose armor was to be the newest exhibit at the museum. The next day, the Mystery Inc. gang arrives at Tokyo, where Daphne is to participate in a martial arts tournament at a prestigious school. The gang meet Daphne’s friend Miyumi, who explains the difficulty of winning the tournament and entering the school as a student. The gang and Miyumi take a fully functioning robotic plane to the school, which is run by Miss Mirimoto. After Daphne defeats Miss Mirimoto’s bodyguard, Sojo, and almost defeats Miyumi, Mirimoto tells her she shows promise as a fighter. Also at the tournament is Mr. Takagawa, who explains to Mirimoto that the Black Samurai has risen and will be after the Destiny Scroll, which is at the school. That night, during a feast, the Black Samurai and his Ninja warriors attack the school and steal the scroll. But Mirimoto explains the scroll was only a copy, and shows the gang the real one. Mr. Takagawa explains to the gang the legend of the Black Samurai.
The Black Samurai was an ancient warrior who asked the great swordsmith Masamune to craft a powerful sword. The sword maker agreed, but told the Samurai it would take a year to make. Masamune’s evil apprentice Muramasa offered to make another sword for the Samurai in only half the time, which the Samurai accepted. But when the Samurai took the sword, the evil of Muramasa was transferred to him, and he became the Black Samurai, wielding the Sword of Doom. When Masamune finished crafting his sword, the Sword of Fate, he presented it to The Green Dragon, who used it to defeat the Black Samurai and imprisoned him in the Sword of Doom. The Dragon then hid the sword, and put its whereabouts in a riddle on the Destiny Scroll."
(Above taken from here... WARNING: Link contains spoilers!)
What can I say? It's Scooby Doo! Who doesn't love Scooby Doo?