He is a Slytherin, a Black, and an ex-Death Eater. Of course he makes it out of the cave.

Regulus sets out to destroy the Dark Lord's Horcrux with no one but a house-elf to help, until he realises his task is bigger than he alone can handle. Reluctantly he turns to the only man Voldemort fears for assistance - Dumbledore - who loans out his pet wolf for the job, much to Regulus's dismay. Together they embark on a hunt for Horcruxes - a long and arduous journey that both makes friendships and destroys them. And a few people get hurt along the way.

Slowburn Wolfstar, Regulus character development, a very flirty (but platonic) Regulus and Remus friendship, and a canonically manipulative Dumbledore.