After going through severe tests, the Kingdom of Arendelle finally returned to its former peace. Queen Elsa (voiced by Idina Menzel), Princess Anna (voiced by Kristen Bell), their friends Olaf (voiced by Josh Gad), Christopher (voiced by Jonathan Groff), and reindeer Sven live a peaceful and comfortable life. But recently, Elsa has always been troubled by a mysterious chant. In order to pursue the truth, she embarked on a journey without hesitation. Worried about her sister's safety, Anna, Olaf, Christopher and others followed closely. In the forest shrouded in thick fog all year round, there are not only mysterious natural forces, but also a series of secrets about the Kingdom of Arendelle, the source of Elsa's magic, and the death of the two princesses' parents. Elsa embarked on a journey of self-discovery...