Carole develops allergic symptoms and fears she has an allergy to horses. She swears Lisa and Stevie to secrecy, but they worry that the allergy is making Carole an unsafe rider. Could this be the end of the Saddle Club?
Out of the blue, Diablo returns to Pine Hollow and Lisa makes him welcome…but Belle falls sick and Stevie becomes convinced that Diablo has brought a killer disease in from the wilds.
Pine Hollow is quarantined by a suspected outbreak of equine influenza. Lisa has to bring Diablo in to establish if he is the source of the outbreak.
A mystery pony appears at Pine Hollow and follows Carole everywhere, which is a good thing since it saves her life.
