In Mitch Albom's new novel, The Stranger in the Lifeboat, 10 survivors from a mysterious shipwreck have been drifting for three days when they pull a young man from the sea into their raft.

He is not injured and without a life jacket.

Sharks have been sighted, and there appears to be no explanation for his presence.

Answers are sought. Where has he come from? And how long has he been in the water?

But the man remains silent.

One of the survivors taps him on the shoulder sympathetically and says, "Well, thank the Lord we found you."

To which the stranger replies in a whisper, "I am the Lord." Prompting an impatiently mocking question: "Are you going to save us?"

Which receives the cool and measured response: "I can only do that, when all of you believe I am who I say I am."

At this point, I was tempted to cast Albom's novel aside. According to his publisher, similar faith-based themes have "touched 40 million hearts", although, as an agnostic, inclined to celebrate doubt, I'm not among them.

However, as a professional reviewer, I know my task is to assess a book on qualities other than personal taste, so I press on.

Since the story claims to be a mystery, I can report that the thin plot does thicken, despite a couple of its promised "twists and turns" placing severe strain my suspension of disbelief - in a literary sense.

But then, I guess, in this narrative country, that's the least of our worries.

Albom is obviously good at what he does. The prose is competent and moves the story forward smoothly.

A luxury yacht, owned by a wealthy man, whose selfish greed has gathered enemies, founders mid-cruise due to an assumed explosion.

The passengers include world famous leaders and celebrities, but also a few hired hands below decks who have reason to hate the ship's owner.

Of course, he is among the lifeboat survivors, along with one of the discontents, who is somehow managing to scribble the novel's narrative text into a notebook as a supposed letter to his wife.

Food and water supplies are precariously low as the self-confessed Lord quietly watches and waits.

Albom is an astonishingly successful author, and I'm sure this novel will be well received by those who love this kind of thing.

As for myself, I shall plead irrelevance and hope for absolution.