Hubie and Marina Find A Troll in Central Park is another Pebble and the Penguin crossover film planned to be made by RogersGirlRabbit (StephanieThePenguin on Vimeo). It will appear in the near future.
The film begins in a Kingdom of Trolls, where Stanley has a magical green thumb with the ability to bring flowers and plants to life at a touch. When he is discovered doing so, the other trolls take him as prisoner to Gnorga, the Queen of the Trolls, who concludes that Stanley "gives a bad name to trolls everywhere" and demands that he be turned to stone. At the behest of her consort King Llort, Gnorga instead banishes Stanley to Central Park where, after a series of mishaps, Stanley hides himself under a bridge. In New York City, two young siblings named Gus and Rosie learn that their father Alan and mother Hilary cannot take them to Central Park. while left alone with their nanny, Maria, Gus takes Rosie to the Park himself.
At the same time, Hubie, Marina and their friends wake up in Central Park, planning a new day ahead.
While playing with Gus's toy boat, Rosie finds the hole under the bridge. Petra, Beanie, Timmy and Pikatwo try to get her out but are curious about the hole under the bridge. They fall in along with Rosie and befriend Stanley. Soon, Gus falls in after them, along with Hubie, Marina, Rocko and Bonkers.
When Queen Gnorga discovers Stanley happy in exile, she creates a flood to drown them by making Gus cry, but Stanley enlarges Gus's toy boat to escape. Soon after, Stanley shows the children, Hubie and his friends his own ideals, depicted as a world of his own.
Determined to suppress Stanley, Queen Gnorga sends a tornado to destroy Central Park, and kidnapps Rosie and Marina. Gus, Hubie and the others, having failed to persuade Stanley's help, face Gnorga. In the resulting fight, Gnorga transforms Gus and Rocko into trolls, while Stanley rescues Rosie, Hubie and Marina. Having arrived, Stanley challenges Gnorga to a thumb-wrestling match, which when Stanley gains advantage, plants roses all around Gnorga's body. As Stanley, Gus, and Rosie escape and celebrate their victory, Gnorga uses Gus's and Rocko's thumbs to turn Stanley to stone. Gus and Rosie fall into their apartment. Hubie, Marina and their friends land just outside their apartment and the last of Stanley's power changes Gnorga into a rose bush. Gnorga, Llort and their dog then return to the Kingdom of Trolls, while Gus returns to his human form.
Rocko, changed back into a penguin, finds Stanley's statue and breaks down. Hubie, Marina and the others comfort him, saying he is not to blame.
The next day, Gus, Rosie, and their parents enter Central Park, where Gus and Rosie help Hubie and his friends place the petrified Stanley on a makeshift pedestal, and Gus attempts to use his new green thumb to revive him without apparent effect, only to find him revived after a moment's pause. Restored to life, Stanley recreates Central Park and covers Manhattan with flowering plants. In the Kingdom of Trolls, Llort takes Gnorga's place as a kinder ruler. Llort is last seen reading a newspaper with "Gnorga: Queen of Posies" written on it, and Gnorga's pet dog bites him for saying that.
- Both The Pebble and the Penguin and A Troll in Central Park were directed by Don Bluth.