>>149029262
The story basically begins like this: Today is Penny's 15th birthday. Gumball and Darwin are helping Penny's dad in the garage, and after a series of missteps, the three end up breaking a mysterious Faerie Rune that only Penny's mom recognized as a family treasure.

After telling the three the story, Penny's dad and mom ask our protagonists to take Penny as far away from her house as possible until the "unwanted birthday guest" is gone.
(This being the Ambassador of the Forest and the first member of the Fitzgerald family who would come for Penny to take her to the Forest and revive the Great Leshen Tree.)

Gumball and Darwin were conveniently going on a trip, and the other Wattersons thought they could celebrate Penny's birthday... in the Forest, where they planned to set up camp.

while the other members of the Fitzgerald Family dealt with the arrival of the Ambassador of the Forest, who was asking for The Last Faerie.

Part 1 predictably ended with the Ambassador discovering that the Wattersons had Penny and, angrily, transforming into a Dragon and taking the Fitzgeralds into the Forest, while strange voices guide Penny deeper into the Forest—voices that are none other than those of all the creatures she transformed into, the Legendary Guardian Beasts.