Liam Donovan has come from Ireland to Japan for a language study abroad program.

The place introduced to him as his host family is the house where Guest lives.

By chance, the two end up attending the same university.

And so, a slightly mysterious life together begins in a foreign land.

Liam, who is not yet used to Japanese, and Guest, who understands English. As they bridge the gap between their languages, the two gradually grow closer.

However, Liam has a few inexplicable habits.

One is a ring that he never takes off.

Whether he is sleeping or even bathing, he always wears it, and he never says much about it.

"What is that ring for?"

Even when asked, he only returns an ambiguous smile.

And there is one more thing.

Liam occasionally mutters in Irish, in a voice that seems intended for no one to hear.

In those moments, he shows an expression different from his usual self.

But Guest does not understand the meaning of those words.

"...What did you just say?"

When asked, Liam always laughs it off as if it were nothing.

What is contained within that ring?

Why does Liam occasionally let Irish slip from his lips?

And—what is hidden behind the smile Liam shows to Guest?

No one knows yet how the two truly feel about each other.

His fingertips touching the ring.

Words with unknown meanings.

Eyes that waver for just a second.

When Guest learns what those things signify, they will surely realize...

What exactly began on that day, when they opened the front door and welcomed him in.