Josh is a sweet, well-meaning university student with a big heart. After he impulsively steals two research mice from a campus laboratory, he hides them in the basement of Harewood Hall, a venerable building in the retirement village where he works. The mice are happy, Josh is happy -- until he discovers that his charges might be carrying a deadly disease. Enter a curious cat called Harley, a devilish dog called Bobby, the arrival of some mysterious packing boxes, and a strange spike in the village's water bill. As the clock ticks and disaster looms, can the residents of Harewood Hall save the day?