It is the year 1347 AD, and a disaster is about to hit. The Black Death is coming, and during the next few years, large parts of the population of Europe and Northern Africa will be killed by the plague.

In Rattus, the players will settle in the various regions of Europe and Northern Africa, while the plague spreads through all these regions. Players gain help from the various professions of the middle ages. Some of these, like peasants and bakers, will help the players grow their populations. Some, such as the monks and nuns, use wisdom and faith to avoid the plague, while the warfare conducted by the knights and soldiers spreads the plague to new areas. However, the plague does not make any distinction. When the rats arrive, no one feels safe. Finally, the plague withdraws and the game is over. Only then will it be clear who was able to keep their population healthy — and win the game!

Rattus: Big Box comes with not only several previous released expansions and promos, but also previous unpublished materials, modules, and bonus cards. More specifically, this renewed edition of the Rattus line includes all materials of the base game and the Pied Piper, Africanus, and Academicus expansions. Additional new content is included, and players can add the new "Guilds & Inns" and "Bonus" modules to give even more variety and challenge.

This edition also comes with popular bonus cards like The Judge, The Jester, and Boccaccio, as well as all 27 level upgrade tiles.