 Roger, Billy and Pete set out to disprove the rumours and superstitions regarding Lac du Diable (Devil s Lake). First they must find Big Joe Lavallee who is the only one who can guide them there. The three get bogged down in a swamp and Big Joe comes along in an ATV to bail them out. Big Joe can t understand why Roger wants to tangle with the devil, but agrees to take him and the boys to the lake the next day. Roger wonders why it is taking so long and Billy, having stolen a look at Big Joe s map before they set out, says they are going the wrong way. When confronted, Big Joe tells them to find the lake on their own. Billy remembers the directions and when the arrive at Devil s Lake, Roger dives below with his camera equipment. Something strange happens, and Big Joe hears a voice telling him to hurry to Lac du Diable to help his friends.