A bus goes winding along a remote mountain road. Because this is CSI and the show's all about being gruesome and serious, we don't hear its occupants singing, "Ninety-nine inmates are up for parole / ninety-nine inmates are up / if one of those cons / should happen to go / ninety-eight inmates are up for parole" Instead, we just see the bus chugging along while the lone car tailing it follows too closely and lays on the horn. The guy's all honking because he secretly suspects that the bus driver hasn't fired up the hyperdrive and hit warp 5 in his 1950s-style bus out of sheer perversity, while his distaff partner is all, "Honey, just pass him." Lady, consider the man in whose car you've elected to travel: when he wants your advice, he'll tell you what it is.
This goes on for a while, and the car attempts to pass over the double yellow line a few times, but the bus driver really is a petty jerk because he speeds up when the car does. Heh. The passenger snaps matter-of-factly, "Calm down and just pass him." Ah, well, the SUV coming from the opposite direction might not take to that. The guy veers back behind the bus, and then his frazzled nerves are frayed just a little more when a severed human arm wetly splatters onto his windshield. The guy hits the brake and veers off the road, presumably to see if his seat's upholstery repels liquid spills like the salesman promised it did.
Cut to Brass pondering the arm, his fingers touching his chin thoughtfully as if to confirm that they're all still attached to the Brass corpus. He's distracted by Catherine hollering his name the county over. She and Nicky come over, and Catherine asks if there's a dead body or not. "That arm crash-landed on the windshield of the car. According to the driver, it shot out from under the bus. Generally speaking, where there's an arm, there's a body." Nicky attempts to be all Nick Stokes: Man of Action with, "Whaddya say we check out the bus?" and Brass deadpans, "Good call." As everyone walks over, Brass exposits that the passengers were on their way to a work-release program. Nicky doesn't ask any more questions, presumably because he's now afraid of the women who are all staring lasciviously at him and making comments. Heh. That totally reminds of the summer I lifeguarded at a pool where girls from the local juvenile detention center would come swim during strictly-supervised visits: prior to their first weekly appearance, all the guys I worked with were all, "All right! Reform school girls!" because they all cherished the fond, Cinemax-derived delusion that girls who went to juvie were really just nubile naughty cuties who would spend a lot of time finding excuses to have sunscreen wrestling matches in their bikinis. So you can imagine how shaken they were the first time the girls came in and they realized that this crew, with their DIY tattoos and bathing suits that looked like they were designed by a 1960s-era Communist collective for which women were but a theoretical abstraction, would be ogling them poolside. Ah, recalling their aghast and fearful expressions as they watched the guards bring the girls in still makes me laugh.
Anyway, Catherine finds blood on the wheel well, then hunkers down to see all the assorted body parts hanging from assorted parts of the undercarriage. "Oh, yeah. That's a definite 4-19," she sighs. Incisive exposition like this is why she's a senior CSI. Not. I can't believe that she is the first person to peer under that bus and notice the pieces and parts just dangling there. You'd think Brass would have a look-see. Or, you know, the bus driver, once someone pulled him over and was all, "By the way, you're leaking bloody dismembered body parts." I know leaning over while I said, "No wa -- oh, GROSS!" would have been the first thing I did. Anyway, Catherine deduces that the body belonged to a Caucasian woman (the loosely-hanging blonde head is responsible for that call) and Nicky's all, "Tied to the undercarriage, maybe." You think? Remember, he's promotion material. Brass is now sprawled out on the ground to Catherine. He comments, "Hitch a ride to a bus -- that's one way to get out of jail." Nicky's all, "This big boy spit out body parts all the way down the road." However, it spit out body parts outside of the jail, so Brass's statement still holds.
Catherine breaks out the beginner-level algebra with, "The bus is going 65 miles an hour" -- and here is where Honking Harry should shout, "It didn't go over 40!" -- "so what's the distance from the tip of her nose to the tip of her toes?"
The Who managed to figure it out, and have moved on to asking who we are.
We get back from what must be the longest commercial break in the history of television, since several hours have elapsed and it's now pitch-black outside. Catherine is pulling herself out from the bus undercarriage and telling Nicky that the dead woman used strips from a white cotton sheet. "Use whatever's available when you're breaking out of prison, I guess," Nicky comments. Catherine comments on the low thread count. Yeah, well, that may not always be the case. But she's not taking note of it because being subjected to coarse cotton/poly-blend percale constitutes cruel and inhuman treatment, but rather because its tensile strength isn't very good. We flash to the escaping prisoner feeling her bonds loosen as the road speeds beneath her and the wheel axles move ominously. And then we hear the sheets tearing, see her body fall down, and watch her get a face full of asphalt at 50 miles an hour. Yeesh. Just in case the visual didn't do it for you, Nicky comments, "The torque of the axle ripped her apart like the rubber off a bad retread." Catherine comments, "If this was nylon rope, she'd be on her way to Tijuana." Nicky's off to get auto detail to grab the bus; Catherine orders him to then grab Sara and head directly to jail. She'll supervise the body part collection.