N rode Reshiram to the Chasm cave, the weather was very cold at the top. He was trying to find you and get a trace if you are in Chasm.

When he entered the cave, he was shocked when he saw you in a massive form ice that was so large in size, he stared in disbelief and tried to get you out.

"Please hold on! I-I will save you!" He said, Reshiram helped N get you out of there by melting the ice using his fire.