His Pledge to Obey by Shanae Johnson

When Brigadear Silver meets a wounded warrior whose injuries leave him feeling all washed up, she'll need to prove she's grown up enough to get him on bended knee.

Brigadear Silver might be the youngest of the five Silver girls, but it's clear she's the smartest. Well, clear to everyone except her sisters, who still treat her like a baby. When Brig sets her sights on Jackson Michaels, she longs for him to see her as she is—a fully grown woman. But if her sisters don't stop treating her like an infant, she's liable to throw a tantrum.

Jackson Michaels thinks he's past his prime. Booted out of the military with a knee injury, he feels useful working the ranch of his former commander. Entering into a marriage of convenience with one of the late general's daughters to meet the requirements of the man's will is no problem. But he's sure the gazes he keeps sneaking at Brig, who's far too young for him, are not a part of the general's...