Colony World

Instruments picked up a regular pulse 37 kilometres down: once every 72 seconds, exact. No geological activity is that precise. And the interval is quietly getting shorter.

The forest on the surface is quiet in a way that is not right — no insect noise, no birds. Worse, the plants sway in a synchrony too neat, as if one thing were directing all of them.

The colony mission's target star, 41 light-years out. Every long-range reading points to habitable. Seen from orbit, it is all but another Earth.