It was hard for many not to feel their spirits sink as their leader fell ill during the battle with an unseen enemy.

The end, of course, justifies the means: to suppress circulation of the unseen enemy, a virus of unknown but potentially vast lethality.

The majority of the 40 regiments carried a red banner depicting a mounted knight, chasing an unseen enemy.

On one occasion, maneuvers to evade the unseen enemy briefly threw the convoy into disorder in dense fog.

In an attempt to drop depth charges on the unseen enemy, the cutter made full speed and the helm was cut hard to port.