Fasten your seat belt-“CSI” is going on a furious ride. On Feb. 4, the team is called in to investigate a death at a high school. “It starts with a kid whose brain literally explodes, and that leads us into the world of classic cars, hot rods and organized street racing”, says exec. producer Naren Shankar. And after a lot of is-she-or-isn’t-she staying, Jorja Fox ends the speculation and rejoins “CSI” full-time. “Jorja will be with us for the whole second half of the season”, confirms exec. producer Carol Mendelsohn. Which is good, because Rascal Flatts guest stars in an episode after the Olympics, and the team will need all the help they can get. Bassist Jay DeMarcus is hospitalized when a gig in Vegas goes horribly wrong. “What everyone thought was an accident isn’t, says Mendelsohn. But the real danger? DeMarcus flirts with Catherine Willows. That could land a guy in real trouble