Imperial Settlers: 3 Is a Magic Number, the second Empire Pack for Imperial Settlers, introduces a new rule: SET. This new ability allows players to score and trigger new effects each time they build three cards in a particular color. With this rule, the drafting phase and the choice of the "right" card to draft becomes even more interesting.

This expansion includes new cards for the common deck as well as new cards for each of the five factions and two cards for use in the solitaire game.