From the publisher's website:

For centuries, creatures have ruled without peer in the depths of the oceans. Their kingdom, Abyss, is respected by all of their allies’ nations, happy to find protection there against fearsome undersea monsters. Soon the throne will be vacant… What if it is time for you to claim it? Time is short! There are only a few days to go before the crowning of the new monarch. To expand your influence and seem to be the only clear choice, you’ll have to explore, recruit, control… Abyss is a development game, a combo-building game, and a set collection game in which players will attempt to take control of the various locations of the kingdom. This takes place on three levels: collect the Allies of your choice which will allow you to recruit Lords, who themselves will grant you access to the various Locations of the kingdom. A first in the world of boardgaming: five different covers are offered for Abyss. Yellow Farmer, red Military, green Merchant, purple Mage, blue Squid, it’s your choice!