Sadin meets the prince in the King's Valley. The prince asked Sadin if he can show him the way to the Forbidden Ruins, but Sadin did not know the way.
Later after the prince acquires a map and returns to the valley, Sadin takes the map and directs him to the Forbidden Ruins, where Sadin points out a map and drawing on opposite walls. After viewing the drawing and ascertaining nothing, the prince looks at the Map while Seto sneaks up behind them and tells them that the Map reveals the location of the High Mages and the Millennium Items. After Seto urges Atem to defeat the High Mages, Sadin yells at him to leave and advises Atem to proceed with caution, since Seto is an enemy and any positive action on Seto's part could be equally dangerous.