Kimagure Orange Road: White Lovers

The gang is at the grandparents' house. Grandpa warns them that lovers cannot ski together, because of a curse. A long time ago, two lovers came to the mountain to hide from their parents, the girl fell into a lava pit and the boy left to get help but she thought he left her to save himself. As such lovers who go to the mountain together will be struck by her curse. The next day Kyousuke and Madoka are skiing together, when an avalanche seals the two in a cave and weird things start to happen. Is this really a ghost's doing!?