He soon went off to sleep again, but was presently aroused by what seemed to him the sound of a short struggle followed by another splash; he dreamingly wondered what it could be and then went off to sleep again.

When he awoke it was daylight.

Somewhat surprised at the non-appearance of Nessus, who usually came into his cabin the first thing in the morning to call him, he soon attired himself.
On going to the door of his cabin he was surprised to find it fastened without.

He knocked loudly against it to attract attention, but almost immediately found himself in darkness.

Going to the porthole to discover the cause of this sudden change, he found that a sack had been stuffed into it, and immediately afterwards the sound of hammering told him that a plank was being nailed over this outside to keep it in its place.
The truth washed across him--he was a prisoner.