The kids and I had just landed in Raleigh-Durham on Monday afternoon when I got the CNN text alert on my phone: “Bombing at Boston Marathon.”  As is typical with me, at first I was completely confused. What do they mean, someone bombed a marathon?! How do you even do that? Why would you do that?

My mother picked us up from the airport. She is a newshound (she regularly falls asleep to the dulcet tones of Rachel Maddow,) so I wasn’t surprised when she whispered in my ear at the baggage claim, “Did you hear about Boston?” I nodded yes and went back to keeping the kids off the luggage carousel. I started to get that feeling that this was not a case of the media making a mountain out of a molehill; I was starting to think that Shit Mountain had indeed plopped down right in the middle of Boston.

When we got back to the house, I went to the TV and turned on CNN. I wasn’t sure I was doing the right thing, because the kids were right there, asking for snacks and wondering why I wasn’t watching Spongebob. I don’t usually watch any kind of adult television in front of them, and certainly not the news, which is the worst of all. But I needed to know what was happening. So I sat there and watched replay after replay of the bomb going off near the finish line. People screaming, running, crying.

Eventually, my daughter wandered over and looked at the screen. She said, “Mommy, what is that?”

And here’s where I made a choice: my twins are five-year-old. They have had an extremely fortunate life so far, in that they have not been exposed to any violence, death, or cruelty. They didn’t know what evil was until last week, when they asked me to define it for the first time. At some point, every child needs to learn that there are shit people who do crap things. I was lucky enough to get to choose a time to tell my kids about that, rather than having it thrust upon them. I thought this was as good a time as any, with an event that was removed enough from their world that it wouldn’t terrify them — a marathon in Boston is not a first grade classroom in Newtown.

Here’s what I wanted to say:

“Well, kids, there are some arrogant sons of bitches in this world who think that their point of view is more important than the lives of others. They decide to speak for an entire group of people, and think that the best way to get their point across and raise awareness for their cause is to blow up an eight-year-old. They are fucking assholes and I will do everything in my power to protect you from them.”

But here is what I actually said:

“Well, sweetie, someone went to this marathon and set off a bomb, and they hurt a lot of people.”

Megan was shocked. “But that is NOT. NICE.”

“No, honey, you’re right. It is not nice. There are some people in this world who try to hurt other people and scare them. There are some people who are not good people.”

Megan thought that over for a minute, and then got the happily sneaky look kids get before they say a bad word.

“You know what else I think?” she said, and came over to whisper in my ear. “I think they are stupid people.”

“You are absolutely right, Megan. They are stupid people.”

So Boston is the event that taught my children that there are bad people. That there are people who hurt others intentionally. That evil exists and that the world is not always the safe place they think it is.

But it also showed them how truly brave and good people can be. That while evil takes plotting and planning, and is committed by a few people who are heartless and cruel, good rises up at a moment’s notice and can be found in anyone: the visitor from out of town, the doctor on her day off, the family member with a cardboard sign, and the runner exhausted after 26 miles. Not just anyone is capable of that kind of evil, but awe-inspiring goodness can be found all around us.

And also, bad people are very, very stupid.