Big If by Mark Costello

Bodyguard blues

Second novels are famously difficult. But Big If, Mark Costello's follow-up to Bag Men, has achieved a fusion of two different storylines into one strong plot, with neither serendipity nor contrivance. Gretchen heads a team of agents assigned to protect the US Vice-President in the closing, flesh-pressing days of his presidential election campaign in New Hampshire. She is hard, sour and grumpy, but the VP is still alive so, to a degree, she is successful.

Her team does not gel. Bobbie is flighty; Elias is phlegmatically Christian; Tashmo glories in his former days as one of Reagan's personal escort; Vi Asplund is 15 years from retirement and feeling vacant with stress. All are slightly ruffled by the bizarre disappearance of Felker. Agent Felker is the author of "the whole theology known as the Dome": overarching protocols of attack, counter-attack, and counter- counter-attack, used by all agents and mapped inside Felker's astonishing memory. If Felker is alive, his knowledge could formulate an unfoilable hit.

Vi's brother Jens is struggling to write code for BigIf, a mammoth computer game set in the post-apocalyptic future. Something about the disturbing realism of his cyber-monsters is blocking his creativity, but jittery venture capitalists make his bosses intolerant of delay. His wife Peta scolds Jens for his lack of application, while throwing herself gutsily into the threats and anxieties of her burgeoning property brokerage, and the tensions of volunteer election work.

The struggle for control - emotional, psychological, logistical - is the common core of these stories. Costello explores it with subtlety and restraint. His skill at slapping messy domestic problems in the face of edgy professional lives offsets the adrenalin and paranoia with a more comic threat.

Big If is low-key rather than epic, but enjoys an expansive sense of "the glorious and accidental world" around its uptight characters. It makes a triumphant second novel, out-geeking Douglas Coupland's Microserfs while sustaining the vigilance of an assassination thriller.