Wilson (Robert Sean Leonard) returns from his leave after Amber's death and talks to House in the season premiere airing tonight on Global and Fox.

House always has maximized its mixture of moral and medical.

But with the fifth season of House debuting tonight (Global, Fox), one of the main emotional ties that holds the series together is at stake:

Can Dr. House and Dr. Wilson still be pals?

House, played exquisitely by Hugh Laurie, is a gruff and grumpy genius with plenty of personal demons, including drug addiction. Wilson, played earnestly by Robert Sean Leonard, is a loyal sidekick who has put up with a lot -- way too much, some would argue -- through the years.

"Almost dying changes nothing; dying changes everything," House says at one point tonight.

With that in mind, how could the relationship between House and Wilson not change after what happened at the end of last season?

As you'll recall, Wilson's girlfriend Amber (played by Anne Dudek) was involved in a bus accident and died due to complications. House was on the bus, too.

Did House directly cause the accident? No. And House, who also had been injured in the crash, subsequently put himself in substantial danger in his attempts to save Amber's life.

But the fact is, the reason Amber even was on the bus was that House had too much to drink in a bar; he called Wilson to come and pick him up; Wilson wasn't home, but Amber was, and she met House at the bar to make sure he got home okay; that's why the two of them were on the bus together.

As the season begins tonight with an episode appropriately titled Dying Changes Everything, it's two months after Amber's death and Wilson has just returned to work. As you would expect, if House is feeling any guilt about what happened, he isn't admitting it to anyone, least of all himself.

House's snappy, cruel dialogue always is amusing, if not cringe-inducing sometimes. When House's boss Dr. Cuddy (played by the hypnotically sexy Lisa Edelstein) asks House how he is going to deal with Wilson, House fires back, "I considered being a horrendous pain in the ass, but I didn't want to tread on your turf."

Truthfully, House isn't sure what he's feeling. Wilson is far more clear-minded on that front, and the conclusions he has come to have far-reaching implications.

While watching tonight's episode, we recalled something Leonard said a year and a half ago at the Television Critics Association tour in Los Angeles. When asked why he thinks Wilson stomachs House, Leonard replied, "At the risk of spreading more wildfire rumours, I don't really see what's so unattractive about House. Maybe I've just been playing Wilson too long.

"What don't you like about (House)? He's shocking and bold and he can be unnerving. But as a friend, I would seek out someone like that, I think."

Hmmm ... we wonder if Leonard would have the same analysis now.

Certainly Wilson has plenty of reasons to consider looking for a new House.