MacKnee was a canine poacher who sought to exploit the legendary Yenkara beasts for profit, capturing a single baby, which Molly Cunningham adopted and named Henry following its escape from a crate MacKnee had locked it in. MacKnee sought the help of Higher For Hire in recapturing what he claimed was a dangerous animal (when in fact Henry was quite gentle), and he managed to convince them until he showed his true side when he attempted to shoot Henry from the sky with little regard for Molly and Kit Cloudkicker, who were riding on Henry's back at the time.
Setting off on his own, MacKnee cornered Molly, Kit, and Henry in the woods, but they escaped and MacKnee was dumped into a river and swept away downsteam. However, he survived and followed them to the Valley of the Yenkara, where he took Molly hostage and demanded that the others help him in capturing every single Yenkara in the valley. Molly though used MacKnee's canteen to splash water on Henry who, like all Yenkara, grew big when wet and sat on MacKnee, subduing the evil poacher. Once they got back to civilization, MacKnee was turned over to the police.