<I>House</i> tries to "unlock" a mystery. House tries to "unlock" a mystery.

8 pm/ET NBC
Superspy Sarah's complex feelings for Chuck are put under the microscope at the behest of agency bigwig Diane Beckman, who last week surmised that Sarah's emotions are compromising her job performance. Enter a sightly but frosty female agent named Alex (Tricia Helfer of Battlestar Galactica), who's assigned to oversee Chuck and evaluate Sarah. Tension soon escalates between the two women, so expect the gloves to come off — foxy-lady style. Then there's that freak-and-geek tandem "Jeffster," who team up with Morgan in an effort to crash Awesome's bachelor party. —Dean Maurer

8 pm/ET ABC Family
Jesse McCartney plays incoming freshman Andy as this college series returns with more second-season episodes. Andy is an old high-school pal of Calvin's, and he becomes an instant hit on campus — so much so that both Calvin and Rusty's fraternities want him as a member. Meanwhile, sophomore Rusty adjusts to living at the Kappa Tau house, while his big sis Casey has secret plans to move out of the Zeta Beta Zeta house. —Jennifer Sankowski

8 pm/ET FOX
House is a patient tonight, but that's not what makes the episode unusual. In fact, it's only a plot device to get him next to the real patient of the week, an injured bicyclist named Lee (Mos Def) who can't move or talk or communicate in any way. The docs treating him think he's comatose, but the patient in the next bed (that would be our antihero, House, who was hurt in a motorcycle mishap) has other ideas. Much of the episode is told from Lee's point of view: You see what Lee sees. —Paul Droesch

CSI: Miami
10 pm/ET CBS
At the end of last week's harrowing episode, Ryan was kidnapped by thugs working for Ivan Sarnoff, the Russian mob boss Horatio recently put behind bars. But he's not held captive for long. Why? They want Ryan to cover up evidence of a robbery-homicide connected to the mob and frame someone else. If he refuses, they threaten to kill Billy Gantry, the young son of Ryan's former Gambler's Anonymous sponsor, whom they have taken hostage. Talk about a rock and a hard place. —Tim Holland

Holiday Hostage Hell
11 pm/ET Travel
Most Travel Channel shows make you want to see the world. This one might make you want to stay home. It details true accounts of travelers who've found themselves in horrifying hostage situations abroad. The series opener tells the story of British botanist Tom Hart Dyke, who was kidnapped by Colombian guerrillas while backpacking in the Darien Gap, and then held captive in the jungle for nine long months. —Karen Andzejewicz