Ep 1. Beyond the Grotto / Lady Rainicorn in the Crystal Dimension

Adventure Time season 10 episode 1 is a double episode titled "Beyond the Grotto" and "Lady Rainicorn in the Crystal Dimension." The episode begins with Finn and Jake discovering a hidden underwater cave where they find a talking magic wand named Wandie. Wandie reveals that he has been trapped in the cave for hundreds of years and asks for Finn and Jake's help to find his missing wand brothers. Together, they set out on an underwater adventure to locate the missing wands.

As they search, Finn and Jake encounter various sea creatures, including a giant squid who tries to attack them. They eventually make it to a mysterious glowing grotto where they find Wandie's wand brothers. However, they soon realize that the wands are being held captive by a dangerous sea monster known as the Grotto.

To save the wands, Finn and Jake must defeat the Grotto. They engage in a battle with the monster, during which Wandie and his brothers use their combined powers to weaken the Grotto's strength. After a long and difficult fight, they finally manage to defeat the Grotto and free the wands.

In the second part of the episode, Lady Rainicorn travels to the Crystal Dimension to visit her parents. However, she soon discovers that her parents have disappeared and sets out to find them. Along the way, she meets a group of crystal beings who offer to help her in her search.

Together, they explore the Crystal Dimension and encounter various obstacles, including a group of crystal wolves who are guarding a mysterious crystal shard. Lady Rainicorn realizes that the crystal shard is the key to finding her missing parents.

With the help of her new friends, Lady Rainicorn manages to retrieve the crystal shard and uses its power to track down her parents. She eventually finds them trapped in a crystal prison, but with the help of her friends, she is able to rescue them.

The episode ends with Lady Rainicorn and her parents returning home to the Land of Ooo, where Finn and Jake welcome them back with open arms.

Overall, Adventure Time season 10 episode 1 is an action-packed adventure that takes viewers on a journey through the underwater world and the magical Crystal Dimension. With its exciting storyline and lovable characters, this episode is sure to keep fans of the show engaged from start to finish.