The Duncans, Ally and Austin Meet Sherlock Holmes is a 2012 animated direct-to-video crossover with Good Luck Charlie and Austin & Ally. The crossover also features the characters from The Suite Life On Deck, Wizards of Waverly Place, Jonas L.A., Sonny With A Chance, So Random!, PrankStars, That's So Raven and Hannah Montana.
In London, an unseen crook begins masterminding his "perfect plot on paper" which starts with a robbery taking place and three cats steal a pink diamond. Three constables spot them and give chase, but the cats escape to the rooftops and glide off into the night, giving the stolen diamond to a mysterious horseman. The next day Dr. Watson rushes to 221B in Baker Street and informs his colleague Sherlock Holmes of the robbery. Holmes calls Teddy and her family to bring him a copy of the Times. Teddy and her family head out to buy it, bumping into Ally and her friends on the way, who has something for Holmes. Teddy and her family send a pile of bricks on Ally and her friends and Ally and her friends give chase. Teddy and her family return to Holmes' flat and hands him the paper or what was left of it. Reading a letter Ally and her friends had given to them, for the night, Holmes and Watson decide to go to the Bruce Nigel theatre and see the fab five named Sonny, Chad, Tawni, Nico and Grady. Holmes is told that she is being blackmailed and Holmes suggests the real perpetrator might be - Professor Moriarty. Holmes deduces that the Star of Punjab, a diamond that is sensitive to the light of a solar eclipse which was to happen the following day, is to be stolen by the mastermind of the blackmail.
At the Punjab Embassy, Alex, Justin, Max, Harper and Theresa are assigned to guard the Star of Punjab. Theresa begins to teach Alex, Justin, Max and Harper how to be a good dog guard, but the three cats steal the diamond while Theresa is not looking. The three cats then step on a small button and retreat. They climb out through a hole that leads to the tunnel and escape before Holmes, Teddy, PJ, Gabe, Charlie, Amy, Bob, Ally, Austin, Trish and Dez arrive. Upon arriving, Teddy tricks Ally into stepping into a broken board and the crew check the tunnel. Finding sawdust, they retreat once hearing Tyke sounding the alarm. Holmes and Watson leave to find the shop from where the button came from, while Teddy, PJ, Gabe, Charlie, Amy, Bob, Ally, Austin, Trish and Dez are left to take Sonny, Chad, Tawni, Nico and Grady to Holmes' flat.
The Police believe Sonny, Chad, Tawni, Nico and Grady are behind the crimes and offer a reward for the one who finds them. Robby Stewart and Jerry Russo move in to take the reward and race to see who gets it. Robby Stewart then bumps into Teddy, PJ, Gabe, Charlie, Amy, Bob, Ally, Austin, Trish, Dez, Sonny, Chad, Tawni, Nico and Grady. They begin a tiring chase and Ally and her friends drop a lantern on Robby's head. They run to the church and they are let in by Cody, Bailey and Mr. Moseby. Cody, Bailey, Mr. Moseby, Sonny, Chad, Tawni, Nico and Grady escape but Teddy, PJ, Gabe, Charlie, Amy, Bob, Ally, Austin, Trish and Dez hid in the organ. Jerry Russo and Robby Stewart then plays a song and send Teddy, PJ, Gabe, Charlie, Amy, Bob, Ally, Austin, Trish and Dez flying.
Ally and her friends catch her back in a pitchfork and Teddy and her family inform Cody, Bailey, Mr. Moseby, Sonny, Chad, Tawni, Nico and Grady that the cats are inside the pub, The Twisted Lip. Sonny, Chad, Tawni, Nico and Grady distracts the cats while guiding Teddy, PJ, Gabe, Charlie, Amy, Bob, Ally, Austin, Trish, Dez, Cody, Bailey and Mr. Moseby to the cats, the former getting punched in the face on the way by a customer (for not bringing his drink). Although, the cats escape in time and kidnap Teddy and her family. Ally and her friends follow them and rescues Teddy and her family, except for the diamond. They are sent flying again, Teddy and her family land to safety, but Ally and her friends lands on a pitchfork. The crew follow the cats to a graveyard and find the diamond. However, a hooded figure gets there before them but Teddy and her family secretly steal the key. Sonny, Chad, Tawni, Nico and Grady decide to go to their friends place, who is a professor.
Sonny, Chad, Tawni, Nico and Grady are brought in by the professor but accidentally bashes Ally and her friends in the face with the door, leaving them, Teddy, PJ, Gabe, Charlie, Amy, Bob, Cody, Bailey and Mr. Moseby locked outside. They then see Robby Stewart and Jerry Russo coming their way and hide in a cabin. Ally and her friends catch Ally's head on a pitchfork again and Teddy and her family are forced to cover their screams. They find the hooded figure's horse and discover that the thief is in the house, also that Sonny, Chad, Tawni, Nico and Grady are in danger! They use the key they got to sneak inside and they find a machine containing the diamonds. Cody, Bailey and Mr. Moseby catch the diamond but slips don the chimney. Teddy, PJ, Gabe, Charlie, Amy, Bob, Ally, Austin, Trish and Dez stumble after them but find that Sonny, Chad, Tawni, Nico and Grady are tied up. The professor captures the crew and reveals himself as Moriarty and reveals his plans to steal The Crown Jewels. By using the diamonds, the eclipse will cover the sun ad the diamond will fire and ricochet of the mirrors and break a hole into the tower.
Moriarty then makes his way to the Tower of London with Sonny, Chad, Tawni, Nico and Grady. Alex, Justin, Max, Harper and Theresa are then left to guard the Crown Jewels but the wall crushes Theresa and the cats steal the Jewels. However, Ally and her friends knock out one cat and trick him into firing the machine on them setting them free. They use the cat's wings to fly to the Tower but Moriarty escapes with the Jewels. Ally and her friends then crash into the carriage and they free Red. Teddy and her family frees the horse and spots Holmes and Watson making their way to Moriarty (who earlier had been deduced by Holmes that Moriarty would steal them). Robby Stewart fails to catch the cats and Jerry Russo sends them into the Tower, where they are beaten up by Theresa.
Moriarty activates his horseless carriage and he and Holmes fight atop the carriage. Ally and her friends accidentally break the brake and the carriage steers off an unfinished bridge. Sonny, Chad, Tawni, Nico, Grady, Teddy, PJ, Gabe, Charlie, Amy, Bob, Ally, Austin, Trish, Dez, Cody, Bailey and Mr. Moseby make it back to the bridge but believe Holmes to be dead. However, Watson arrives and finds Holmes clinging to an edge with the Jewels. Moriarty and the three cats are arrested but Jerry Russo gets the reward instead of Robby Stewart.
At the church, Cody marries Bailey and they start howling and run off. While Holmes and Watson watch them run off, Teddy then secretly sends Ally's foot on fire and Ally gives chase to Teddy. It is then revealed that Mitchel Musso also does weddings, and Mitchel Musso smiles at the screen.
- Bridgit Mendler as Teddy Duncan
- Jason Dolley as PJ Duncan
- Bradley Steven Perry as Gabe Duncan
- Mia Talerico as Charlie Duncan
- Leigh-Allyn Baker as Amy Duncan
- Eric Allan Kramer as Bob Duncan
- Laura Marano as Ally Dawson
- Ross Lynch as Austin Moon
- Raini Rodriguez as Trish
- Calum Worthy as Dez
- Cole Sprouse as Cody Martin
- Dylan Sprouse as Zack Martin
- Brenda Song as London Tipton
- Debby Ryan as Bailey Pickett
- Doc Shaw as Marcus Little
- Phil Lewis as Mr. Moseby
- Selena Gomez as Alex Russo
- David Henrie as Justin Russo
- Jake T. Austin as Max Russo
- Jennifer Stone as Harper Finkle
- David DeLuise as Jerry Russo
- Maria Canals Barrera as Theresa Russo
- Joe Jonas as Joe Lucas
- Nick Jonas as Nick Lucas
- Kevin Jonas as Kevin Lucas
- Nicole Anderson as Macy Misa
- Chelsea Staub as Stella Malone
- Demi Lovato as Sonny Munroe
- Sterling Knight as Chad Dylan Cooper
- Tiffany Thornton as Tawni Hart
- Brandon Mychal Smith as Nico Harris
- Doug Brochu as Grady Mitchell
- Allisyn Ashley Arm as Zora Lancaster
- Audrey Whitby as Audrey Vale
- Matthew Scott Montgomery as Matthew Bailey
- Shayne Topp as Shayne Zabo
- Damien C. Haas as Damien Johannssen
- Bridgett Shergalis as Bridgett Cook
- Mitchel Musso as Himself
- Billy Ray Cyrus as Robby Stewart