Jake told this far-fetched tale about a huge fish that had gotten away and susan muttered under her breath, "and that's about the time the clock struck 13."
The novel's opening sentence is "It was a bright cold day in April, and the clocks were striking thirteen."
This sentence suggests three things. First, with the clocks striking, it suggests a known situation: a human city where clock bells chime. Second, when the clocks strike 13 rather than 1, it tells us everything is different. What's more, it isn't a single clock doing this, but all: this is a unified society, or trying to be one. Third, 13 is traditionally an unlucky number. This is the number of the last supper, and suggests someone will be betrayed and die.
THE CLOCK THAT STRUCK 13 - Pemberton Greenish