Splash!
"Y-Your Highness!"
The knight scrambled to his feet the moment he realized he was alone on the wooden platform.
"Your Highness, can you hear me? Your Highness? Miss Esther?"
Sir Galien was torn between calling the attention of the patrolling city guards and diving into the river himself. He was aware that the Crown Prince knew how to swim, and he should be able to resurface on his own. The knight could not understand what had just happened, and after waiting for several excruciatingly long seconds, he realized there was no change in the dark waters of the river.
'Perhaps His Highness swam to the riverbank to avoid the invisible attacker?'
However, that part of the river was dark, and it was impossible to see anything clearly beyond what a normal person could see under the soft light offered by the moon.