What would you do if you knew you only had a few months to live?

That's the question that Showtime's new series, "The Big C," has asked for 10 weeks so far this season. It's an essentially spiritual question that has been answered with maddening candor, great humor and, increasingly, abundant grace.

The show is built around Cathy (Laura Linney), a high school teacher, wife and mother in suburban Minnesota who is dying of cancer. Last week's episode, titled "Divine Intervention," found Cathy facing up to the consequences of her reckless choices in the weeks following her diagnosis.

Until last week's episode, Cathy had been keeping her fatal condition a secret from nearly everyone closest to her, including husband Paul (Oliver Platt). Her one confident, apart from her oncologist, is her cranky next-door neighbor Marlene (Phyllis Somerville), a widow battling the early stages of Alzheimer's disease.

For most of her life, Cathy has been a good girl. She married young, made a beautiful home for her family and was unfailingly practical, right down to her perfectly pressed khaki pants.

But news of her impending demise knocks her world out of orbit. She begins to indulge her fantasies, from digging a hole for a backyard pool to getting her first Brazilian bikini wax and embarking on an ill-conceived affair.

For much of the series' inaugural season (it's just been renewed for a second), Cathy's adventures in newfound freedom were entertaining. I even found myself cheering her on. Still, I began to wonder when and if the other shoe would drop.

In "Divine Intervention," Cathy found some much-needed clarity and solace -- even if it was delivered with a slap across the face.

When Cathy blithely tells her neighbor-confessor that Paul is divorcing her because she had an affair, Marlene smacks her hard, telling her that cancer doesn't give her the right to be a "destructive b***h."

"Sorry about the slap," Marlene says.

"Somebody needed to," Cathy answers.

When Cathy's favorite student threatens to quit school, in part because she knows about Cathy's affair, the teacher tracks her down at church choir practice to try to talk her out of it.

It's a fool's errand. But on the way out, Cathy spots a sign that

reads: "Need a do-over? Our God is the God of Second Chances." It's not exactly a burning bush or pillar of fire, but it might as well be.

Cathy returns to church on Sunday in pursuit of her prodigal student, and during the pastor's sermon about "do-overs," she stands to ask for prayer. The monologue that follows is a beautifully articulate expression of repentance, redemption and grace.

"Pray for me. I've lied. A lot. I keep on lying and I'm sitting on a huge pile of lies right now. I've cheated on my husband. I've had an affair and it's hurt people I didn't expect it to hurt," Cathy says.

"There is some stuff that I can control and then there's this other stuff that's, um, it's killing me. Pray for me. Oh help me, God. If there is a God, and I hope that there is because I have to believe that there's going to be someone on the other side who's going to leave the light on for me when I get there, that there's going to be someone there to welcome me. Pray for me."

"The Big C" is absolutely stellar storytelling. It's spiritually smart and brutally honest. It treats faith with respect and tenderness, portraying it in all its complexities and foibles and comforts.

As Cathy grapples for a rudder to steer the drifting ship of her soul, faith isn't her last resort, but rather the answer she's been seeking, a light in the darkness of grief and despair.

But it's not the easy answer. It requires action, not just belief.

Cathy has to make amends to those she's injured and begin the process of mending broken relationships.

On "The Big C," faith is as difficult, confounding and entirely necessary as it is for so many of us in "real" life.

Life is short, the show's writers tell us, too short to waste it on petty grievances, and hollow selfish indulgences or to allow disharmony and division to fester.

It's also too short not to have hope, choose love, and cling to what St. Paul calls the substance of things hoped for: faith, the evidence of things not yet seen.

Cathleen Falsani is the author of "Sin Boldly: A Field Guide for Grace" and the recent book, "The Dude Abides: The Gospel According to the Coen Brothers.")