Three patients sneak their pets into the hospital, causing pandemonium in the ER.

A patient appears to be hallucinating and sends ER staff on a wild goose chase; a new nurse makes a shocking mistake; doctors try to help a former EMT who was found lethargic and slurring his words.

A surfer is impaled between the legs; a football player's severe leg pain leads to an unexpected diagnosis; a woman is given a clot-busting drug to cure her stroke, but she has another condition that could cause that same drug to kill her.

A boa constrictor has wrapped around a man's arm and won't let go; a young woman has a severe laceration, but doctors begin to suspect there may be more to her case than the injury; a young man goes into anaphylactic shock after a dinner out.

An urgent care physician must think outside the box to care for two emergencies at once; a woman with abdominal pain receives an unexpected diagnosis; a yoga instructor has a dangerously high temperature for no obvious reason.

A patient is brought to the ER with a live shark clamped onto his thigh, and he wants to save the shark! Complications arise for a woman with a life-threatening condition, and the mysterious condition that caused a man to pass out.

Police officers bring in a criminal that is comatose; a man found passed out in the snow with no jacket or shoes arrives in the ER and a doctor is faced with a family emergency on her day-off.

A fishing lure embedded in a man's face turns out to be the least of his problems; a pair of unconscious teenagers get brought to the ER, where dramatic family secrets come out; an ER technician collapses and refuses traditional medical treatment.

A man's itchy rash turns out to be more than just poison oak; a young woman bleeds profusely from the inside of her lip, but there is no obvious cause; a family of three is admitted as car accident victims, but the doctor makes a shocking discovery.

Two separate car crash victims are brought to the ER in their underwear; a woman is acting delusional and refuses to allows the ER staff to touch her; and a doctor struggles to diagnose a dehydrated and nauseous 10-year-old.