We were in the same rectangular room where we’d started studying karate together when we were seven. A mirrored wall ran along one side, with a framed photograph of Dr. Chitose, the founder of the Chito-ryu style of karate, hanging above it. The other walls were mangy gray, equal parts old paint and smoke from the pool hall that shared the hallway with the Higashi School of Karate. Around the dojo were black-lettered banners saying things like Only those who have patience to do simple things perfectly can do difficult things easily. At seven, I’d been a pocket-sized cynic who read that as a hackneyed cliché. That hadn’t changed.

“You suiting up to spar?” I asked.

“Facing off against you in a mood? No, thanks.” She set down the duffel bag she was holding. “Tiger Mom is worried you’ll get rickets from living on protein bars. She cooked for you.”

“She’s the best,” I said.

“You say that because you don’t live with her anymore,” Reagan said. “Last Saturday, I slept in until eight, and she lectured me about wasting my life. I told her I worked seventy hours last week and got a spiel on how hard she and my dad had to work when they were our age.”

“I like that she’s tough.” Reagan’s mom was named Vera, but I could only think of her as Mrs. Chen. She was incredibly kind, but also bracingly direct and opinionated. Now that Caro was gone, Reagan and her mom were the closest thing I had to family. When Reagan’s dad had gotten sick with a brain tumor when we were ten, my best friend had practically moved in with my family. She stayed with us for the two years Mr. Chen suffered through before he died. Then Reagan and her mom had taken me in when I was a teenager who couldn’t live in her parents’ house anymore.

“She’s kind of worried about you.” Reagan crossed her arms. “She figured we’d hear from you after the funeral. I told her you’d be hiding out like a wounded wolf.”

“It wasn’t just the funeral. It was . . .” The words died on my lips. Reagan knew me well enough not to say anything. I took a few breaths from my diaphragm. That was one thing karate had taught me that I carried everywhere. “What would you say if I told you there’s something suspicious about my sister’s death?”

Reagan didn’t flinch. “She died suddenly, and no one knew she had a heart condition. You could call that suspicious.”

“More than that. Something else.”

“Is this about a feeling you have, or evidence?” Reagan was a data analyst, and I had yet to meet anyone whose work matched their personality better than hers. She had a photographic memory and the ability to recall conversations perfectly. It could be annoying sometimes, because she questioned everything.