The first episode of the show sees the Stark family coming across a litter of direwolves. It is Jon who convinced Ned to allow the other children to keep the cubs, even discounting himself as a Stark in order to do so. However, they find a 6th wolf - an albino one - which Jon takes as his own and names Ghost. The two have been together ever since, bar the occasional moments of Ghost being locked up, and they have been shown to have an extremely strong bond. Jon, however, doesnt know just how strong that bond can be. Bran possesses the ability to skinchange, able to possess his own wolf and other creatures, even humans (Hodor!), and while Jon maybe cant go that far, he is able to warg into Ghost, something he hasnt yet discovered on the show. Hopefully he will soon, as it may be the thing that saves his life.