It's 1914, the beginning of WWI. In White River, Ontario, en route to a training camp in Valcartier, Québec, with the Winnipeg section of the Canadian Army Veterinary Corps, Army Lieutenant Harry Colebourn, who has a natural rapport with animals, saves a black bear cub from being killed by a hunter, who killed the cub's mother. Not knowing what else to do with the cub, Harry brings her along to camp to act as the unit's mascot, who he names Winnie - short for Winnipeg. Most of the men in the unit bond with Winnie, but having such a mascot is against the wishes of the head of the Canadian Expeditionary Force's veterinary division, Colonel Barret. Barret is a tough but fair man, who may have more problems than Winnie in the form of the Expeditionary Force's commanding officer, General Hallholland, a dipsomaniac who uses his position in the army for his own vainglorious purposes. Winnie's stay with Harry and the unit is not always a smooth one, especially in trying to stay under Barret's radar. Over time, Winnie becomes completely tame, craving human companionship, which Harry realizes is a problem as the unit is scheduled to get shipped overseas to England and eventually to France to do their duty on the front lines. Sending Winnie back into the wild may no longer be a viable option, as Winnie has a mind of her own, but finding a home for her where she will get the human companionship she craves or else possibly die from not having what she needs - which means an owner that understands that she's no ordinary bear - may be a problem.