The CDC, the U.S. Army and a Bronx Zoo veterinarian join forces to identify the disease rapidly filling the city's emergency rooms and curiously killing 17,000 crows and zoo birds in NYC. Then, an unidentified virus tears through the Southwest.

Recipients of a single organ donor exhibit the same bizarre, manic behavior before lapsing into comas. Then, in the Midwest, a mysterious and terrifying pox outbreak has left more than 70 patients plagued by strange, pus-filled lesions.

Violent flu-like symptoms strike down men in the college town of Fort Collins, Colorado. Then, an elderly woman who just returned from China is rushed to a Northern Virginia hospital. Has this woman brought a terrifying disease to US soil?

Hundreds of injured soldiers returning from the Middle East bring back incredibly powerful mutant bacteria. Also, the CDC is flooded with reports of severe illness in children across the country - an invisible assassin is on nationwide killing spree.

After a huge earthquake hits California, a deadly fever is spreading quickly, and it's likely caused by a fungus released by the quake. Then in another story, a horrendous bacterial outbreak forces one of the largest food recalls in U.S. history.

Dr. Jeff Young & his crack team treat and save the lives of countless pets at one of the busiest clinics in America. In this episode, Jeff is faced with saving a dog that goes into cardiac arrest shortly after arriving at his clinic.

A 3 month-old micro pig with an injured leg requires surgery, but anesthesia could be deadly. A French Bulldog's routine dental exam becomes a complex operation. The team heads into the Rockies to help a couple who rescue sled dogs.

Dr Jeff and his team are pushed to the limit when a litter of 10 puppies comes in with a mysterious and deadly disease. Then, Dr. Jeff must work out what's wrong with a limping cat before performing complex hip surgery.

A dog is brought into the clinic with a suspected broken leg, but Dr. Jeff quickly diagnoses a far more serious condition requiring urgent surgery. Vet tech Tasha is forced to overcome her childhood fear of birds.

A golden retriever is rushed into surgery after swallowing a pacifier. When a stray dog is hit by a car in Oklahoma, Dr. Jeff & his team step up to save him, but they'll need to find the dog a home once he has recovered from surgery.

When a homeless man’s puppy breaks its paw, Dr. Jeff & his team put the animal’s welfare ahead of everything else. And when a dog in pain is brought in, x-rays reveal one of the worst cases of bladder stones the staff has ever seen.

A devastated owner rushes his golden retriever in after accidentally breaking her leg while playing with her. Then, a beagle is dumped at the clinic after a vicious dog attack & it’s up to Dr. Jeff to fix him up & find him a new home.

Rookie vet Dr. Amy’s surgery skills are pushed to the limit when fat cat Chubbs is rushed into the clinic with a serious facial injury. Meanwhile, Dr. Jeff helps a Labrador whose rear-end has been peppered with buckshot.

An overweight cat with kidney disease needs a miracle if it is going to survive. And, Dr. Jeff battles to save a dog hit by a car while the owners are on an overseas mission.

With the holidays approaching, the clinic is busier than ever. Dr Jeff performs surgery on a dog found tied to a fence. The staff hosts a fun run to raise money for animals in need, and a stray Pomeranian finds its forever home.

In Mexico, Dr. Jeff treats a dog with a painful looking growth and Drs. Petra and Nichols help a dog seriously injured in a fight. The team also tries to catch and treat a pack of feral dogs.