In the Season 4 premiere, a black Lab swallows toxic metal; a lost cat is found after a one-and-a-half year absence, but has a mysterious injury; and a tiny dog has a big, life-threatening problem.

Dr. Jeff performs emergency surgery on a pit bull and makes a surprising discovery. Dr. Baier treats a goat kicked by a horse. A couple drives all night hoping the team can fix their dog's shattered leg. And an injured ostrich is taken care of.

A high-risk surgery is attempted to save the life of a beloved puppy; a 3-day-old orphaned kitten needs Dr. Baier's help to stay alive; a puppy is given a fifty-fifty chance of survival after it's rushed to the clinic with a deadly virus.