This story is actually pretty unique for a race game :D
Jak and Daxter are called to Kras City (I think it was kras city) for the reading of Krew's will. As a hologram, he made before his death, Krew says he wants them all to drink a little something-something he's been keeping just for the occasion.
And afterwards they find out (also from Krew) that it was poisoned! And the only way to get the antidote is to win the next race cup.
The gameplay is awesome ^^
It's a battle-race game. That means it's basicly like mario-kart. BUT it's not at all like mario kart because this game is so much faster and waaaay harder :D
For instance: When you use your weapons enough, without dieing your Dark Eco guage will fill. Once it's full your weapons will be even stronger! These weapons are the best out there. Like if you would normally get 2 homing missiles, with dark eco you get 4.