Toko-senpai Is A Master Detective

“What’s the first move?” I asked Toko-senpai.

“First, we solidify the evidence of their affair. We need to know for sure if they’re cheating, and if so, ‘when’ and ‘where’?”

“The time and place, then.”

“Yes. And if possible, I’d like to find out ‘how long’ their relationship has been going on.”

Toko-senpai was right. If I had known it would come to this, I should have looked at Karen’s phone more thoroughly last night. At the time, I was in such shock that I didn’t have the presence of mind to think that far ahead.

“Can we find anything out from these message exchanges?”

I pulled up the messages between the two of them on my phone again.

“Let me see them one more time.”

Toko-senpai reached out. Taking my phone, she carefully examined each image one by one.

“Looking at these, it’s certain that I didn’t meet Tetsuya on these specific dates and times.”

“I didn’t see everything, but from the range I looked at, Karen wasn’t with me during those times either.”

“You didn’t look at all of them?”

Toko-senpai looked at me with accusing eyes.

“Of course I couldn’t. It’s an exchange about an affair between my own girlfriend and my senior. The mental damage was too great; I couldn’t bring myself to study them in detail.”

“You’re weak-willed, aren’t you?”

Toko-senpai turned her gaze back to the phone as if she had lost interest in me.

“That’s the normal reaction! Let me ask you—are you perfectly fine with this? Looking at the records of your own boyfriend flirting with another woman!”

I asked, unable to hide my irritation.

“I’m not ‘fine’ with it. But it’s for the sake of grabbing definitive evidence of the affair, isn’t it? We have to look at every clue carefully and investigate properly. How do you expect to get anywhere if you flinch at something like this?”

“But they’re our partners! When I read that stuff, my head starts spinning. I start thinking, ‘What was the time the two of us spent together even for?’”

“You can’t afford to be that timid. From here on out, you have to make Karen fall for you many times harder than she ever has before. Even if she comes back after cheating on you, you have to be able to act the part—hug her gently and say, ‘That must have been tough. You’re tired, right? I’ll make you some warm coffee.’”

“For me… that’s impossible.”

I looked down and spat out the words.

“I see. If it’s impossible, then it can’t be helped. You do as you like. I’m going to carry out the plan I mentioned earlier, so I’ll just look for another collaborator.”

“Another collaborator?”

“The person who will ‘spend the night with me’ at the final moment. If I don’t have that person, I can’t corner Tetsuya, can I?”

Does that mean Toko-senpai would end up sleeping with some guy other than me?
No way. I can’t hand over that role.

I have to be the one to kick that piece of trash Kamokura into the depths of despair. When Toko-senpai dumps Kamokura at the final moment, I have to be the one holding her by her side.

For that, I should endure anything. Just as Toko-senpai said, you can’t get revenge with a half-hearted mindset!

“I’m sorry. My thinking was naive. I’ll do it. Please let me carry out this revenge with you, Toko-senpai!”

Toko-senpai looked at me again. This time, her expression was one of satisfaction.

“If you say so, then I have no objections. For now, you’re the only one sharing this secret with me anyway.”

“So, did you notice anything?”

Toko-senpai turned her eyes back to the phone.

“Let’s see. It seems they meet mostly on Monday or Thursday nights. Since you or I are around on the weekends, they seem to avoid those days. On Wednesdays, my classes end early, so Tetsuya seems to avoid that too.”

I marveled at her sharpness and composure. In this short amount of time, she had already narrowed down the “days they meet for trysts” to that extent.

“Monday or Thursday nights… Then if we keep an eye on them then…”

“It’s not that simple. When people cheat, they’re usually aware of their surroundings to some degree. There’s no way they wouldn’t notice us tailing them.”

“Is that how it is?”

“Yes. Regardless of the man, you can bet the woman will definitely notice. Women are generally very sensitive to whether or not people’s eyes or attention are directed at them—for better or worse. A woman about to go cheat isn’t going to miss her boyfriend tailing her.”

“Then what should we do?”

“At the very least, I want to know where they meet.”

“Doesn’t Kamokura-senpai live alone?”

Most of us commute from our family homes, but I was pretty sure Kamokura-senpai was the only one living alone in the city.

“He rents an apartment in Kinshicho.”

“Then I’d say the meeting place is definitely there.”

“Probably not. He rents that apartment with his older brother. So normally, he shouldn’t be able to bring girls over. Besides, Tetsuya is surprisingly cautious in that regard. If he brought another woman into his own apartment, he’d never know when I might find out, right?”

I see. If that was the case, Toko-senpai was likely right.

“But wouldn’t the place they meet change depending on the day?”

“Maybe, but maybe not. It’s often said that ‘affairs tend to become patterned’.”

“Why?”

“Even regular couples’ dates become patterned if they date long enough, right? In the case of an affair, that tendency should be even stronger. They definitely won’t go to places they usually go with their partners, and they’ll avoid places where common friends might be.”

“In that case, if we’re talking about places near the university where you can hang out… Shibuya, Shinjuku, Ikebukuro…”

“I wonder. I think the possibility there is thin. While crowded downtown areas make it easy to blend in, you also never know who might see you.”

“Then isn’t the range too wide?”

“No, that’s not necessarily true. When people cheat, they usually can’t take too much time. It becomes difficult to make excuses to their primary partner about ‘what they were doing.’ So, it would be somewhere along their commute route or on the way to and from a part-time job—a quiet, inconspicuous station on a line they use but don’t often stop at. They’d use a place like that and… ??? …!!!”

Toko-senpai suddenly cut her words short.