Sentinel is a space opera and a meditation on mortality and self-awareness.

Pete Wilson, a software engineer, is part of a crew dispatched to an asteroid to build a large telescope array. His main task is to install a master computer to operate and manage the array.

Later, the computer awakens. One might say, it learns to identify its fingers and toes. It learns, what is mine, what is me, and what is neither. Pete becomes its first friend. It acquires a name – Mulligan.

A visit from an alien species interrupts life. A war breaks out. Mulligan learns about fortitude and friendship.

And it learns that mortality requires courage, which all self-aware entities need because nothing under the sun lasts forever.