The following is a mystery divided into five acts. Each week, readers will vote on the way they want the story to progress in the next act. You have five weeks to figure out the mystery.

Get an audio version of the story here.

The Aurora Express: Act IV (4)

I’ve been letting Tyasia lead this investigation the whole time, despite my own intuition that she knows more than she’s letting on. I decide that it’s time I follow my gut.

“Maybe we do need to search Olivia Green’s room,” I tell her, “But I’m going through that journal with you.”

I see a momentary crease of annoyance across Tyasia’s brow. If I wasn’t looking for it, I would have missed it completely. “But we’re wasting valuable time—”

I look her straight in the eye and decide to be direct. “Is there something you’re not telling me, Tyasia?”

“I—what? No, I just want to find Dr. Foster.”

I put out my hand. “Let me see the journal. Now. Or I’m going to Commander Xu.”

Suddenly, Tyasia smiles, as if trying to disarm my suspicions. “Okay, okay. I’m not hiding anything from you. I’m just really worried about Dr. Foster.”

I roll my eyes at her and thumb through the journal. Every entry is even more cryptic than the others, but as I’m about halfway through, a small slip of paper falls out. It reads:

Username: lgfoster

PW: mycelium2841!

I look up from the slip of paper. Tyasia looks at me and takes a deep breath.

“Ok,” she says with a sigh. “You’re about to find out about everything anyway, so here’s the deal. I’m not pretending to be a detective. I am a detective. I was assigned to the ship by the Nova Interstellar Community Consortium because we received word that there was likely a spy from ExoTerra Expedition Enterprises aboard the ship, but we didn’t know who.”

“But why would there be a spy from EEE on here? And didn’t NICC do thorough background checks on everyone on the ship?” I ask.

“Of course we did thorough background checks. Someone apparently got through anyway. You don’t get it. Dr. Foster’s research about using mycelium to build organic buildings will change the entire face of planetary exploration. Not having to constantly cart supplies from Earth opens up so many possibilities for self-sustaining colonies.”

I stare at her for a minute. Finally, I have to ask, “What’s mycelium again?”

She takes a deep breath. “It's fungus, basically.”

“Like mushrooms,” I ask.

Tyasia explains, “Kind of. Mycelium is the network of thread-like filaments that form the vegetative body of a fungus. It's similar to a plant's root system. And it’s perfect as a building material on Mars because it’s lightweight, strong, and grows quickly using minimal resources. Its insulating properties would help protect the community against Mars’ extreme cold, and it could potentially also protect us from cosmic rays. It can be grown using waste and easily regrown in case of damage.”

“But Dr. Foster is a botanist. She studies flowers, not fungus.”

“No, she’s actually a mycologist—one of the best in her field. Botany was her cover.”

“And Octavius knew about her actual work?”

“Yes. He’s here representing patent interests on her work,” Tyasia tells me.

“You mentioned a spy. Who do you think it is?”

“Well, my first thought was Jordan Ramirez, just based on how much time she was spending with Dr. Foster. I think Jordan has a vague idea of how the whole mycelium building thing works, but as we’ve been investigating, there’s another suspect I’m more worried about.”

“Olivia Green,” I say.

“Olivia Green,” Tyasia confirms. “I think she actually was a sixth grade science teacher, but she’s shown far too much interest in Dr. Foster’s work. Mycelium needs cyanobacteria to grow properly, and I have a feeling that Olivia may have been sabotaging the cyanobacteria cultures to prevent Dr. Foster from completing her work.”

“Does Commander Xu know any of this?”

Tyasia sighs again. “Commander Xu knows why Dr. Foster is here. She doesn’t know why I’m here, or that there’s likely a spy from EEE on board the ship.”

“So that’s why you didn’t want me to go to her.”

“Right.”

“Okay, so now what do we do? Do you think Olivia has done something with Dr. Foster?”

Tyasia bites her lip. “I’m not sure. Remember how Jake Harris said that Dr. Foster kept slipping away to ‘go do science?’ I’m almost wondering if she had a secret lab somewhere on the ship. Clearly she wouldn’t want to be doing her actual work with the mycelium where anyone could see.”

I nod thoughtfully. “Especially if she also suspected Olivia Green.”

“Yeah. Exactly,” Tyasia says.

I run my fingers through my hair. “Ok, so what do we do next?”

“The way I see it, we have a few options. We can confront Olivia directly, though I’m not sure that’s wise if she really is the spy. We can use this username and password to try to log in to Dr. Foster’s account and see if we can find any clues from her research. But…there’s one other person I’m convinced must have been in on the secret: Dr. Basu. She’s the only one who could have caused the system malfunction to Lily Foster’s biostat link so that it’s not pinpointing Dr. Foster’s exact location at all times. I think that means that Dr. Basu is on our side, helping Dr. Foster be able to do her experiments in secret. But…she could also be covering for Olivia Green, if Olivia actually did something to Dr. Foster.”

I stand back on my heels and try to think through the best course of action.