The conversation happened late Saturday night, after Victoria had gone to bed and the house had settled into its deepest quiet.

Elena sat on the edge of the master bed in the dark, sweater still on, the renewed bruise on her breast aching every time the fabric shifted. Marcus stood near the window with his back to her, looking out at nothing. The close call from that afternoon still sat between them like a third person in the room—the vacuum running downstairs, Rosa’s footsteps, the half-second too long that her eyes had rested on them in the kitchen.

“We have to change how we do this,” Elena said. Her voice...