Into the Unknown - From Frozen II. Composers Kristen Anderson-Lopez and Robert Lopez have once again written music for Disneys sequel film Frozen II after great success in 2013 with Frozen. Many will probably remember Let it Go which became a big hit from this movie. The new movie continue to follow the main character Elsa, who sings her amazing musical number ?Into the Únknown? in Frozen II. The song describes Elsa's inner conflict of choice to leave Arendelle or trace the source of a mysterious voice she continues to hear. The song is originally sung by Idina Menzel and the Norwegian artist Aurora and has elements and motifs inspired by Scandinavian herding calls. As always, the music is both magnificent and captivating and will surely be a hit for many years to come.