9 p.m. Tuesday, Sept. 25

In most cases, a ratings graph for a hit series has a sharp incline followed by a gentle downward slope. That might also have been the case for "House," now entering its fourth season, but now there's a change in the prognosis. The Fox series, created by David Shore, returns in the fall with a major cast shake-up, new stories, fascinating characters and lots of vitality.

In the first three seasons, the brilliant but irascible Dr. House (Hugh Laurie) worked his diagnostic magic with three interns (Omar Epps, Jennifer Morrison and Jesse Spencer). When last season ended, two resigned to take jobs elsewhere, and one was fired. In the season premiere, House insists to no avail that he can do without a team. In the second episode, a medical version of "Apprentice," he begins whittling down the 40 applicants to three.

There's still the bizarre case of the week but now it's not just the patient who's getting infusions. "House" itself is teeming with new blood. The array of new faces and styles are just what the doctor ordered. So much so that it will be sad to see several of them depart in the coming weeks.

As for the three former members of House's team, they didn't get far. All are back by the second episode, albeit in different capacities.