“We’ve done it your way,” Mackenzie said as she switched on her computer and sat down at the desk. “Now we do it mine.”

“What’s your way?” I quipped. “We send our suspects strongly worded emails?” I flopped on the bed.

“We’ve been going about this randomly,” she said, without taking her eyes off her computer screen. “We need to think things through logically.”

I thought there was a dig at me in there somewhere. “OK. So what do you suggest?”

“We make a grid—”

I interrupted, “Oooo, a grid.”

She glared at me. “Do you want to find out who is behind this or do you want to crack jokes?”

I shrugged. “I think I can multi-task, as you might say.” I stood behind her.

“Motive, means and opportunity,” Mackenzie said as she typed the titles into each column of the grid on her computer. “We create our suspect list and then assess if they could have done it and why.”

“We know it has something to do with Ingenium International College,” I said. Every terrible thing that had happened was swirling inside me. My body was vibrating with it. I started to pace. “Lucinda, Alexia, Mr Ashworth, Blake, TnT and loads of the guests have connections to that school.”

“You’re doing it again.”

“What?” I shouted. “I’m being logical.”

“You are jumping in at the middle,” she explained. “Let’s go through our suspects one by one.”

I groaned. This was going to take for ever. We were stuck in here while the killer was escaping, or worse yet planning another murder. “Shall I list them alphabetically by height or favourite colour?”

“Stop taking the mickey.”

“What?” Sometimes we really did speak different languages.

“Stop making fun of me. If you give my way a chance, we could solve the murder without disobeying Ariadne.”

She was right and that burned even more. “Where do we start?”

“Everyone’s a suspect until we rule them out.”

“That’s going to be a pretty long list.” It felt pretty hopeless, but I kept moving and thinking.

Mackenzie stared at her computer screen, her hands poised over the keys. “We can’t possibly know everyone’s motives, but we can look at means and opportunity.”

My face scrunched in confusion.

“Who had the ability and the opportunity to commit the crimes?”

Three short and sharp knocks on the door made us jump. “Are you girls OK in there?” Sven called through the door. Grandma must have asked him to check on us.

“Yeah, we’re fine,” I called. “What about Sven?” I whispered to her.

She typed his name at the top of the chart. “Means?”

“He’s young. He’s strong. He owns those scary looking carving tools. He knows this place because he helped build it.”

She typed everything I said in the grid. “Opportunity?” she asked.

“He constructed the ice bed where Lucinda was found?” I said.

“And he was one of the first to arrive at the ice cathedral when you were screaming for help.”

“What about poisoning Alexia?” I asked. “Did you see him at the party?”

“No, but he could have sprinkled on the fish flakes earlier. And just because we didn’t see him doesn’t mean he wasn’t there. The problem with this place is that we all look the same in our Winter Wonder snow gear.”

“He doesn’t have any connection to Ingenium International College,” I added and walked behind her so I could see what she was doing.

“That we know of.” She typed furiously.

We both gasped when a mugshot of Sven appeared on the computer screen. We must have been louder than I thought, because Sven knocked on the door again. “What is going on?” he called and jiggled the door handle.

Did he have a master key? “We’re changing clothes!” I called and pressed my body against the door as if that might stop him. We didn’t need him barging in and seeing his name at the top of our suspect list.

“OK. Sorry.”

I looked through the peep hole. He sat down across from our door and closed his eyes. He was standing guard. Had Grandma asked him too? He didn’t seem too bothered that a killer was on the loose. Maybe because he was the killer. I tiptoed to Mackenzie.

“Sven Thomsen,” she whispered, “was convicted of breaking and entering when he was a kid. He was sentenced to a rehabilitation program, which seemed to turn his life around. In the last few years, he’s won loads of awards for his ice sculptures.”

“How can you possibly know all that? His mugshot and criminal history can’t be on the internet.”

She smirked. “You can find almost anything if you know where and how to look.”

Sven wasn’t the only criminal around. I was pretty sure that Mackenzie was breaking a few laws. Having a hacker as my best friend was proving to be very helpful.

“Any connection to Ingenium?” I asked.

“Not that I can find.”

“Any connection to Alexia, Lucinda or Blake?”

“Nothing.”

“So he’s an ex-con, but not a killer.”

“We can’t rule him out. He has plenty of means and opportunity.”

“But no motive.”

“That’s the tough part. He’s got no motive that we can find, but it doesn’t mean he doesn’t have one.”

“Who’s our next suspect?”

“Katrina has a motive even if we don’t know what it is.” Mackenzie typed Katrina Memering under Sven’s name. “We saw her fighting with Alexia and later cuddling Blake. Who are you, Katrina Memering?” Mackenzie’s fingers flew over the keyboard. She clicked on links, opened databases, processing the info and moving on before I could understand what she’d done. If there was a world championship of hacking, I bet she’d win the top prize.

“Very strange,” Mackenzie muttered.

“What?” I said. Mackenzie didn’t seem to hear me. “What?!” I said it louder this time.

“All I can find is information on her current job, articles she’s written for a variety of magazines and clients. I can’t find any connection to Ingenium International College or anything more than a few years old.”

This reminded me of my struggle to find out more about my mom. “What if she’s like Ariadne? Ariadne uses her maiden name. What if Memering is her married name or her mom’s maiden name or a name she made up?”

I paced the room again. Mackenzie clicked and tapped madly for a few minutes. “You are a genius!”

I smiled. No one had ever called me that before.

“I searched variations on the name Katrina and then checked birth certificates based on the bio on her website then I cross-referenced social media with—”

I stopped in front of her. “Yeah, yeah, but what did you find?”

“Katrina Memering used to go by the name of Trina Blanchett, and I need a drum roll please…”

“Get on with it!”

“Trina Blanchett went to Ingenium at the same time as Alexia and Blake.”

You are a genius!” I said as we high fived.

“Means and opportunity?” Mackenzie asked.

My excitement fizzled. “She couldn’t have sabotaged the dogsled. She arrived after that happened.”

Mackenzie thought for a moment. “She said her plane was delayed, but we only have her word for it. She could have arrived a day or two earlier.”

“Or she could have hired someone to do it too,” I added. As hard as it was for me to believe, people did that.

“What about when Alexia was poisoned?” Mackenzie asked when she’d finished typing our notes in her grid.

I remembered the moments before Alexia was poisoned. “The plate of food that Alexia ate from was originally Katrina’s. Don’t you remember they argued right before Alexia collapsed?”

“Actually Katrina handed her plate to Shauna and Alexia snatched the plate from her.”

“Yeah, yeah, but the point is she had time to sprinkle the fish flakes on the plate. In the commotion she had plenty of time to throw away the vial of fish food.”

“So you are saying she poisoned her own food in the hopes that Alexia would pick a fight and take her plate?”

“When you say it like that it doesn’t make any sense.”

“Do you think Katrina is allergic to shellfish too? It’s a common allergy.”

“Or maybe there was poison in the vial. We haven’t analysed the contents. Maybe someone used the smelly fish flakes to cover up the poison.”

“But Alexia recovered when you gave her that shot.”

“We don’t know what’s happened to her since she left the resort, do we?” My brain was putting the clues together. “Maybe Katrina was the real target.”

“Or the killer,” Mackenzie added.

“We know one thing for sure,” I said. “Katrina is mixed up in this.” I handed Mackenzie her snowsuit and started to slip into mine.

She hugged her snowsuit. “What are you doing? Ariadne said we are not to leave this room. What are you thinking?”

I tugged on my boots. “That Sven is guarding our door so we’ll have to leave by the window.” I yanked it open and the icy air stung my cheeks. Luckily we were on the ground floor.

“We agreed that we would stick together.” She threw her snowsuit at me.

“I know.” I threw it back. “So come on.”

“Sticking together means that you stay here with me.” Mackenzie crossed her arms across her chest as if tying herself in an immovable knot.

“Sticking together means you don’t let me go out there on my own,” I said, and climbed out of the window. I paced in the deep snow making two trenches as I waited for Mackenzie. I made it all the way to the end of the building. I peered around the corner. Two snow-suited figures were heading this way. I ducked back out of sight. I’d been spotted. If that was Grandma or Shauna I would be in the biggest trouble of my life. They’d probably lock me in a broom closet somewhere until this was over. I dashed to our window as Mackenzie was climbing out.

“We knew you two would be up to something.”

I recognized the voice – TnT.

“What are you doing here?” Mackenzie asked.

Then I had a sickening thought. Mackenzie was right. We should have finished our list. It would have definitely included TnT. They were always sneaking around and running off. They attended Ingenium.

“What are you doing?” Toby, or was it Taylor, asked right back. “We heard about what happened to that Blake guy. Whatever you are up to, we’re in!”

I didn’t know if we could trust them. They were our age. Could they really be murderers? I knew age didn’t matter. Teenagers killed all the time. Were they smart enough to have planned one murder and two attempts? I studied them. They’d played those pranks on us. That took planning – and there were two of them. Together I was sure they were capable of a lot.

“We were going to follow Sven,” I lied. Mackenzie narrowed her eyes in confusion but didn’t say anything. “He’s got a criminal record, did you know that?”

“No,” the boys said in unison.

“He’s guarding our door, but we thought maybe we should watch him.”

“Sort of like a stake-out,” one boy said. They bounced with excitement.

“Yeah,” I said. “Can you keep an eye on him and report back?”

They nodded. “What are you going to do?”

“You guys are much better at this kind of stuff,” I said but one hundred per cent did not believe it. “We’ll stay in our room. We aren’t supposed to leave anyway.”

As the boys dashed off, Mackenzie started to climb in the window.

“What are you doing?” I asked.

“I thought you said—”

“I’m not sure we can trust them. I needed them out of the way.”

“So we are still going to disobey Ariadne and hunt for the killer,” she said with a groan. She thought that by saying it matter-of-factly like that I’d see the crazy of my ways.

Nope.

I said, “Yep!” without hesitation. Because what she forgot about me was that I liked crazy.