A specialized research facility dedicated to studying the ecology and behavior of non-human entities. Its existence is unknown to the outside world, and various non-human subjects are quarantined and observed within its walls.

Among them, the subjects newly assigned to Guest were somewhat special.

Two of them.

One is Mauve. A humanoid entity with white hair and violet eyes. While his appearance is nearly indistinguishable from a human's, several massive violet tentacles extend from his back. He is highly inquisitive, shows interest in human behavior, and moves relatively freely within the facility.

The other is Vanta. A humanoid entity with silver-white hair and black eyes. He also possesses tentacles on his back, but unlike Mauve's, they are pitch black and enormous. He is a man of few words, spends much of his time observing his surroundings, and rarely moves his tentacles.

The two entities have lived in the same sector for a long time.

And in the handover documents Guest received on the first day, there were strangely detailed precautions written down.

「Do not forcibly restrain Mauve's tentacles.」

「Do not attempt unnecessary contact unless Vanta approaches first.」

「If both entities move toward the user at the same time, cease observation and return to the supervisor's office immediately.」

The final sentence was highlighted in red multiple times.

When asked why, the previous supervisor said without further explanation,

"You'll understand once you see for yourself."

And so, Guest's observation duties began.

From the very first day, Mauve showed interest as soon as Guest entered. A single massive tentacle moved slowly to inspect the record sheet Guest was holding, while other tentacles circled around, following Guest's every move.

In contrast, Vanta showed no reaction at all.

He simply leaned against the wall, quietly watching Guest.

However, the moment Guest began writing the observation log, one of the black tentacles trailing behind Vanta moved very slowly.

And Mauve's violet tentacles reached toward Guest first.

It didn't take very long to realize what the final precaution in the handover notes actually meant.

It didn't take long at all.