INSIDE BURNING BUILDINGS, Captain Caleb Holt lives by the firefighter's adage: NEVER LEAVE YOUR PARTNER. Yet at home, in the cooling embers of his marriage, he lives by his own rules.

Growing up, his wife Catherine always dreamed of marrying a loving, brave firefighter . . . just like her father. Now, after seven years of marriage, she wonders when she stopped being "good enough." Countless arguments and anger have them wanting to move on to something with more sparks.

As they prepare for divorce, Caleb's father challenges him to commit to a 40-day experiment:...