“Ahhh… Today is the last day of summer vacation.”

Kei said that, sitting down on the bed making a ‘pah’ sound and raising her head to look at the ceiling sadly.

In order to reveal our relationship gradually in the second semester, I and my girlfriend, Karuizawa Kei, had been having regular secret dates. Today would be the last of those dates.

Even though I couldn't fully concentrate when I spent time with her, it was not uncomfortable at all.

If we were friends who didn’t know each other well, we might feel restless having to find words to talk about.

“Starting from tomorrow, it would be fine for me to tell others about my relationship with Kiyotaka… I am kind of nervous.”

“You don’t need to force yourself to tell others. I won’t take responsibility if your status in the class falls.”

“I will say it absolutely. Even if anything happens, it’s alright because you will protect me, right?”

Although Kei seemed to be joking, it was without a doubt her true feelings.

As a parasite attached to a strong host, Kei was protecting herself.

I finished the last sip of my coffee and sat down next to Kei.

When I held her slim hand, she gently returned my gesture. Kei turned towards me, looking embarrassed.

"Kei"

At that moment, I laid my lips over her soft lips.

"Ki-Kiyotaka..."

"Surprised?"

"Y-Yes, I was. C-Couldn't you have let me know in advance...?"

I didn't reply to that question with words, but with actions.

I gently grabbed her shoulders and drew her close to me.

"Hmph...!"

The second kiss. Once our lips touched, Kei's shoulder made a little leap in surprise.

Our lips shortly separated, and as if relieved, her eyes looked at me with reluctance.

"You caught me by surprise again..."

“Really? I thought it was quite normal.”

I would have to learn the timing to kiss by doing it repeatedly.

“At least, my heart isn't ready yet…...”

“Then, how about now? Are you ready?”

“Eh? ...Yeah…”

While nodding and saying that, Kei closed her eyes. After seeing her being ready, I kissed her again.

The two kisses until now only lasted around one second, but it was different this time.

5 seconds, 10 seconds, and longer…

And then we gradually moved our lips, repeating the kisses like small birds pecking each other.

During this frozen passage of time where it seems like there was only the two of us...

We were in our 2nd-year of high school. On the last day of the summer vacation, I and Kei learned about kissing and took another step forward in our relationship.

The first half of the curriculum of love had ended, and we had begun the second half.

From now on, both of us would openly live our school lives as a couple.

As a result, we might get into some troubles, but we would face the difficulties together hand in hand.

Although slowly, we were definitely taking small steps forward, as the seasons change from summer to autumn, from autumn to winter.

We would dye our relationship with our deep, deep colours and make it indispensable to us.

While we were repeatedly confirming the taste of our lips, my thoughts were involuntarily drifting towards the future.

When the season of farewells would finally come, this romance would meet its conclusion—

Because it's already fated to meet an utmost difficult trial.

Karuizawa Kei would need to stand up and face what lies ahead even if she broke away from her host.

That was the most important part in this curriculum of love.