Following the trail of Prince Roland, six brave adventurers venture into the Darkside, the other side of the world Xeen. There, a mysterious person who calls himself Lord Alamar has defeated the local queen and usurped her throne. Allies of the Dragon Pharaoh, the Guardian of Darkside, have either joined Alamar or perished in their resistance. The Guardian bestows his powers upon the adventurers, who must liberate Xeen and eventually help the space traveler Corak to finally destroy the corrupt Guardian Sheltem for good.

Darkside of Xeen is the fifth installment of the Might and Magic, a direct sequel to Clouds of Xeen, and a completion of the overarching story arc that started in the first game. The game uses the same engine and interface as Might and Magic III: Isles of Terra, and is nearly identical to its immediate predecessor gameplay-wise. Compared to earlier games, it has a darker and somewhat more bizarre setting, and dungeon exploration involves more puzzle-solving. It is also more plot-focused and has a larger number of cutscenes.

All over the game's world there are pyramids which work as teleporters as soon as part five of the series, Darkside of Xeen is installed. The two games can be played simultaneously, merging into World of Xeen, which includes multiple cross-over quests in both installments.