Journey back to The Unknown as Wirt and Greg take refuge in a mysterious woodland hospital known as Benevolent Sisters in Charity Infirmary & Asylum. However, with a no animals allowed policy, their best friend Beatrice is forced to stay outside! Even so, the hospital seems too good to be true, with friendly nurses who seem to have nothing to do but pamper them! But when they discover that there are no other patients in the hospital, the nurses behavior takes on an all new meaning! It's up to Beatrice to save the day -- but what is the horrible secret of the Benevolent Sisters?