From the back of the box:
"Each player gets eight cards. The player who is the first one to put all his cards on the table is the winner. But Beware! There are peculiar action cards which can turn everything upside down. SOLO is a new variant of Mau-Mau with special action cards, that will guarantee a lot of fun."
Each turn, a player can put a card with the same colour or number or action symbol as the card played previously. The special action cards allow players to:
* Miss a turn - next player misses their turn
* Change direction - the order of play is reversed
* Take 2 - next player draws two cards
* Choose a colour - can be named as any colour, changing the colour in play
* Take 4 + choose a colour - you choose a colour, next player picks up four
* Swap cards - choose another player and swap cards with them
* Change all cards - all hands move round one space in play direction
The Miss a Turn, Change direction, Take 2 and Swap cards are colour coded and must be played following a card of the same colour, the Choose a colour, Take 4 + choose a colour and Change all cards actions are colour independent.