When my teenage daughter, Rachel, saved up for months to buy a sewing machine, I never expected her stepmother, Karen, to destroy it out of spite. Rachel had worked hard at a part-time job to afford it, and I had even offered to match her savings. But when Karen threw the machine in the pool over a minor chore disagreement, I knew it was time for revenge.

Rachel’s dad, Mark, did nothing to stop Karen, which only added to my frustration. I quickly took Rachel home and comforted her, but I also began planning a payback. With help from my friend Jason, an actor with an old police uniform, we devised a plan. The next day, Jason, posing as a police officer, showed up at Karen’s house to “confiscate” her laptop. Panicked and pleading, Karen realized the severity of losing something important to her, just as she had made Rachel feel.

As I stepped inside, I told Karen she’d have to apologize and pay Rachel back. She reluctantly complied, handing over a check and muttering an apology. Rachel and I left victorious, and from that day on, Rachel stayed with me full-time, visiting her dad only when she wanted. As for Karen? She’s been on her best behavior, but she’ll never forget that lesson in empathy.