Howland Reed = Bowen Marsh!
In the early days after the rebellion Howland saw in a green dream how important Jon was going to be and that Ned wasn't going to live to see Jon into adulthood, so he decided he was going to have to take the boy's destiny into his own hands. He knew that Benjen knew the truth behind Rhaegar and Lyanna's relationship, so he revealed Jon Snow's true identity to him and recruited him into his scheme.
Benjen would plant the seed, luring Jon into the Night's Watch, where Howland would be under cover to keep an eye on him. Jon got sorted into the stewards not because Mormont wanted him to rule, but because Howland, who had become head steward, wanted to keep him close. That all went awry when Jon saved Mormont's life and Mormont brought him on his ranging beyond the Wall.
Then, after Jon returned to Castle Black, when the Lord Commander election came up, Howland tried his best to keep Jon from winning, because he was afraid Jon would choose his position as Lord Commander over his duty as king. Once again, though, Howland wasn't prepared for Sam's expert politicking.
Howland became increasingly worried as he saw Jon grow close to Stannis, as he was effectively aiding the cause of a rival claimant, and when Jon was ready to ride against the Boltons to avenge Stannis he knew he had to act, so he launched his stabbing party, but not before he prepared some bit of bog magic maybe, like, a frog-gut poultice or something? to stop Jon's blood flow and keep him alive through the attack.
Winds is probably going to open with Jon regaining consciousness and finding himself strapped to the back of Howland's frog-mount that he kept hidden under Castle Black, hopping away toward Greywater Watch where Howland will reveal everything to him.