In Shinobi Empire, you are trying to lead your ninjas to infiltrate the castle quicker than all the other players. Infiltration is not enough though, you must get your ninjas to the room where intelligence are gathered.
You do not know the internals of the castle at the beginning of the game but as the game progresses, the castle will slowly reveal itself. This is accomplished by players playing cards to introduce hallways, ninjas and walls to each floor. Players are trying to make the biggest room possible with the presence of their ninjas by capping a hallway with walls. Only the single biggest room will count though: Open ended hallways and rooms tied in size do not qualify.
The first player to successfully places 7 ninjas of his clan in the largest rooms in the castle wins!