Now Darvin looked over at her and gasped. She looked back at him, her lips curling upward, and produced a soft, furry moan. Their faces were almost touching, their breaths mingling in moist little puffs. Their hands roved beneath the blanket like a couple of warm, burrowing animals, hers delving industriously into his unzipped and unbelted pants, his digging deep under the hem of her dress.

Darvin was about to reach the unquestionable high point of his journey--or this leg of it, at any rate--when the fluorescents running over the middle aisle abruptly flickered on, flooding the train with their stark radiance. Startled from her rapture, Christina from Ipanema straightened beside him, her hand becoming frustratingly still under the afghan, then slipping all the way out of his pants. She looked around in distracted confusion. Most of the dozing riders had been awakened by the sudden surge of light and were doing the same. Though Darvin remained dug in under her dress, figuring he'd stay there until explicitly asked to leave, he likewise found himself glancing about the coach. It wasn't just that the lights were on. It was that they were buzzing loudly and seemed much too bright, as if their wattage had been turned up to a hot, glaring level. And the attendant, who was staring up at the ceiling of the car, looked as bewildered as everyone else.

"O que e isto?" a guy behind him asked loudly in Portuguese. "Tudo bem?"

What is this? Is everything okay?

Seconds later, the speeding train jolted on the track and the emergency horn in the locomotive burst into clamorous, ear-splitting sound, making it clear that everything was very definitely not okay.

Minutes after that, Darvin, the woman who called herself Christina, and twenty-five other passengers aboard the car were dead.

When they were young and struggling to meet the rent in the Baltimore rowhouse apartment where they'd raised their four children, Al and Mary Montelione had played a silly little game with each other virtually every time they went to the supermarket. It had started soon after their next-to-youngest, Sofia, was born. Because they'd been living exclusively off his modest postman's salary and had needed to cut comers wherever possible, they would very carefully compare prices on grocery items, household supplies, really anything and everything they purchased.