He Will Always Love Me

SOILERS FOR HIS DARK MATERIALS BOOKS BY PHILIP PULLMAN.

Set in a alternate version of what happened after the Amber Spyglass, Lyra and Will did get to remain together, Will stays in Lyra's world and together they become explorers.
However, when Lyra and Pan get separated from Will and Kirjava and the group of researchers they're traveling with in the North, Lyra and Pan find themselves lost in a storm and both end up unconscious in the snow.
Will and Kirjava set out and find them, but after being out for hours in the cold and unconscious, it is deeply worrying when the man and his Daemon find them.

I picture them to be around 19/early 20's in this.

(Also available on Archive Of Our Own, under TheSevenWondersOfAWitch)