The literary device foreshadowing refers to the use of words or phrases that set the stage for the story to unfold. It gives the reader a hint of something that is going to happen without revealing the story or spoiling the suspense. Foreshadowing is used to suggest an upcoming outcome to the story.
“He had no idea of the disastrous chain of events to follow”. In this sentence, while the protagonist is clueless of further developments, the reader learns that something disastrous and problematic is about to happen to/for him.