After meeting the force led by Lord Commander Jeor Mormont at the Fist of the First Men, Qhorin Halfhand selects Stonesnake, Harker, and Borba for a scouting party to ambush a group of wildling lookouts. They are joined by Jon Snow. They locate and surprise the lookouts, killing all but one of them. Jon is left to execute the wildling survivor. Jon does not return and they return for him. They pick up his tracks but are ambushed by wildlings. Harker, Stonesnake and Borba are killed while Qhorin is captured. Jon had spared the captive and she leads him into a similar ambush. Qhorin seizes the opportunity to insert Jon as an infiltrator in the wildling ranks by berating him for the deaths of the others publicly.
In the Song of Ice and Fire novels, Stonesnake is also a Ranger serving under Qhorin Halfhand. He's dubbed Stonesnake for his ability for climbing mountains and cliffs.
In the novels, his fate is uncertain. After his horse panics and breaks its leg, he offers to stay behind and fight the pursuring Wildlings like Dalbridge, but Qhorin orders him to make it through the Frostfangs afoot to the Fist, and to tell Mormont what they saw. Jon watches Stonesnake goes away, and fears that he has no chance. Stonesnake has not been mentioned since. While it has not been confirmed that he died, according to the novels appendix he was lost afoot in Skirling Pass.