Radio psychologist Jack Black takes his children Joshua and Ashley on a 'vacation' to a lake in British Columbia. While he grinds away at work the children discover that the famous local lake monster Orky may not be just a gimmick to attract tourists after all. In fact, Orky may enable them to get closer to their workaholic dad, and help stop local polluters who are dumping toxic waste. Two siblings find out about a mythical aquatic monster and try to a save a remote Canadian lake from being used as a dump site for toxic waste.