Stross's disorganized fifth Merchant Princes story (after 2007's The Merchants' War) continues the adventures of hapless Boston journalist Miriam Beckstein. Newly free of political imprisonment, pregnant and on the lam, she finds herself at the center of a desperate power grab as political instability rocks the mafia-like Clan Corporate, who are magically able to cross between parallel worlds. When world-walkers steal nukes from a U.S. installation, it's a race against time to find out who has them, and why, before they can be deployed. The U.S. is also close to discovering a technological method of world-walking, rendering the clan both vulnerable and obsolete. Stross pays heartfelt homage to Roger Zelazny and Lois McMaster Bujold, but with too many characters and too little focus, this novel fails to match their achievements