From the back of the box:
THE GAME IN A NUTSHELL
Cards with color-coded letters create crafty new ways to score.
Make words from cards of mixed colors
From cards all the same color (scores double)
With "straights" of three or more consecutive letters
With starred cards that double or triple the value of words
With "flushes" (five or more cards all the same color, no word necessary)
By "building" on words played by opponents
In other shrewd and wily ways
Get help from three wild cards that can be substituted for any letter or any color
Zap your opponent's big score with point-canceling "killer-card" (Joker)
Game ends when all cards are used. Highest total score wins.