Object of the Game
During the six rounds of the game, place your divers in order to gain the upper hand in the five great domains that are Science, Exploration, Navigation, Engineering and War.
The player who has won in the most domains will be declared the winner at the end of the game.
The gameboard is placed between the two players. The Diver cards are shuffled then placed in a pile at the front of the Nautilus, face down. The special cards are shuffled then placed in a pile at the back of the Nautilus, face down. The Domain cards are shuffled. Five of them are placed faceup on the five empty spaces of the game board. The remaining cards form the draw pile which is placed next to the game board, face down. The youngest player gets the Nemo token, thus becoming the first player of the round.
Preparation of the Round
Before starting a round, each player gets 5 Diver cards, which they look at secretly. Then the first player draws two special cards. After having looked at them, the player keeps one and gives the other to his or her opponent.
Some special cards can be played at the beginning of the round and others during the round.
To start, the first player places one of their Diver cards face up, along the Nautilus and in front of a Domain card, either on their own side or on the side of their opponent. Then, it's up to that opponent to do the same and so on until the 10 spaces (5 on each side of the Nautilus) have been filled by a card.
Some Diver cards have horizontal or vertical arrows. When they are played, these cards cause a movement action.
At the end of the round, the value of the Diver cards placed face-up, on both sides of the Nautilus, will determine who gets the Domain cards in play.
End of the Round
The round ends as soon as all 10 spaces on both sides of the Nautilus have been filled by a card (Diver or special). The Domain cards are then awarded. A player gets a Domain card when the value of the Diver card on their side is higher than that of the one on the opposite side.
End of Game and Scoring
The game ends at the end of the 6th round, when the pile of Domain cards is empty.
Each player takes the pile of Domain cards won during the game. In each of the 5 domains (Science, Exploration, Navigation, Engineering, War), the players will compare their totals: two stars are worth 2 points, one star is worth 1 point, an ink blot removes 1 point from the concerned domain.
The player with the highest points score in a domain wins that domain. The player who wins most domains wins the game.