Radio psychologist Jack Black (Mark Harmon) takes his children Joshua (Joshua Jackson) and Ashley (Sarah Wayne) on a "vacation" to a lake in British Columbia. When he slaves 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 keep local polluters from dumping toxic waste into Orky's home.