Mystery! Action! Songs! Join Detectives Mary-Kate and Ashley as they undertake daring adventures. Pack your gear and help the Trenchcoat Twins investigate the danger that lurks. Along with their sidekick dog, Clue, Mary-Kate and Ashley promise to "solve any crime by dinner time." In this episode, the Olsen and Olsen Mystery Agency has been hired to find the ghost in a haunted mansion in Transylvania!

The pint-sized twins this time are headed to Deald Gulch, USA to explore the mystery of the missing cattle at the Logical I Ranch! It's up to our detective posse to solve this ten-gallon case before high noon.

The twins investigate a mystery at Sea World in Florida.

On board the "Fun Ship," the twin detectives find fun and solve crimes while soaking up the Caribbean sun.

In this episode, the pint-sized private investigators take a spin on spine-tingling amusement park rides and then team up with some hilarious pirates-of-the-midway to catch the scary monster that lurks inside the freaky Fun House.

In this episode, the sly sleuths are busy wrapping holiday gifts and learning carols when a call from the Three Wise Men sends them in search of The Spirit of Christmas! Now, it's up to the dynamic duo to use all their computer smarts and solve this holiday crime by Christmas time!

In this episode, the super sleuths are called in to help out the Space Program and Mission Control with the help of Alan Bean of Apollo XII, the 4th astronaut on the moon. Unless they solve the mystery of the unknown ticking sounds and the grounded U.S. Space Shuttle, the Shuttle cannot lift off as scheduled!

In this episode, the adventurous twosome take on the undersea case of three pirates who swear that the sharks are actually singing!

There's trouble in paradise! Join the twin detectives, Mary-Kate & Ashley Olsen ("Full House"), and their sidekick dog, Clue, as they check in for excitement at the Hilton Hawaiian Village Hotel.

The girls receive a call from some miners of marshmallows that a snowball-throwing monster has been "terrorizing" them. The girls eventually find out that the "snow" is really ash, and the "monster" is actually a geologist warning them that an active volcano is not a safe place to work.

Travel with the pint-sized supersleuths, Mary-Kate and Ashley Olsen ("Full House"), and their sidekick dog, Clue, to the Edge of the World, where a fleet of UFOs have been flying over Earth every 93 minutes.