Opening with Elsa's previously-seen attempt to skip across the surface of a turbulent ocean, she is engulfed by an enormous wave; but beneath the water she catches a glimpse of the mythical entity in the form of a horse, who is said to use the power of the ocean to guard the secrets of the forest.
"Elsa, the past is not what it seems, you must find the truth," the Grand Pabbie troll, voiced by Ciaran Hinds, informs her. "Go north across the enchanted lands and into the unknown."
Indeed Anna, Kristoff, Olaf and Sven are seen traveling through the sumptuously animated frozen landscapes, even passing Elsa's glacial castle on the way, while the ice queen herself gets to grips with some fancy new frost tricks.
"But be careful," Pabbie warns her sister. "We have always feared Elsa's powers were too much for this world... now we must hope that they are enough."
"I won't let anything happen to her," a determined Anna (Kristen Bell) replies.
The final shot sees Elsa hiding from yet another new creature, a towering stone golem.
"Frozen 2" reunites the dream team of directors Jennifer Lee and Chris Buck, producer Peter Del Vecho and songwriters Kristen Anderson-Lopez and Robert Lopez, as well as Idina Menzel as Elsa, Jonathan Groff as Kristoff and Josh Gad as the lovable snowman Olaf.
The 2013 original, the highest grossing animated film of all time, won two Academy Awards, for Best Animated Feature, and Best Original Song ("Let It Go")