Secrets Can Kill is a computer game from a company called Her Interactive, which came out last November. My parents gave it to me for Christmas. It's the first time anyone has ever made a real Nancy Drew mystery that you play yourself, and it's on CD-ROM for the computer.

In the game, you are Nancy. A student at a high school has been killed, and Nancy goes undercover, pretending to be a new student, to find out who did it. You walk around the school, search everywhere and read everything, and most of all you talk to people. Every conversation gives you choices of what Nancy says, and what you choose matters.

I've played it all the way through three times. The first time took me about two weeks of after-school time. The third time took two afternoons, because I knew what I was doing, and I still found things I'd missed.

1. Talk to everyone twice. Then talk to them again later. People say different things once you've found something new, and sometimes the most important thing a person says is the thing they say the second time.

2. Write your clues down. I kept a spiral notebook next to the computer the whole time, with a page for each suspect and a page for every number and name I found. Nancy would. You will need it. There are things you find early on that don't make sense until much later.

3. Save often. Nancy can get into real trouble in this game, and some mistakes end it. Save before you go anywhere you're not supposed to be. Save before you try anything risky. Just save.

4. Look at everything. Click on every drawer, every paper, every bulletin board. Most things aren't clues, but the ones that are, you'd never guess.

5. Don't accuse anybody in your head too early. I did the first time and it made me miss things that pointed somewhere else.

6. If you're truly stuck, take a break and come back. Every time I got stuck, the answer was something I'd already seen and not thought about.

Here are the four main suspects and how suspicious I thought each one was the first time I played, before I knew anything. One question mark is "probably not," five is "definitely them." I am not going to tell you whether I was right. That would ruin it, and Nancy doesn't tell either until she's sure.

My advice: rate them yourself, then change your ratings every time you learn something new. I changed mine about ten times. That's how it's supposed to work.

Four and a half stars out of five. It's not perfect. Walking around takes a while, and some of the puzzles are hard in a way that's more frustrating than fun. But for the first time, I didn't just read about Nancy solving a mystery. I solved it. That feeling when it all came together was the best part of my whole winter.

My mother played it after me, with my notebook, which I think is cheating. She says it's "research." I hope Her Interactive makes another one soon, because we're both ready.