The phrase "a complex plot" is correct and usable in written English.
It can be used when describing a narrative or storyline that has intricate or complicated elements, often found in literature, film, or theater.
Example: "The novel is renowned for its complex plot, which weaves together multiple characters and timelines."
Alternatives: "an intricate storyline" or "a convoluted narrative."
Within the tangle of gags, there is a complex plot.
That was a complex plot for any show.
It has a complex plot, explained with short video scenes, and animated graphics and moody music.
Some investigators doubt that he had the leadership capacity to have written such a complex plot and theorize that another suspect will prove to be the ringleader.
A complex plot, suffused with the nightmarish quality of Twin Peaks, and a tough-minded, resourceful protagonist add up to a stand-out read.
A shame, given some great characters and a complex plot that both felt like they could have done with a more definite resolution.
The old mates' conflicts with their younger wives - Clara, "from Lambeth (via Jamaica)", and Bangladesh-born Alsana - and their "second-generation" children form the core of a novel with a bizarrely complex plot and a prodigious cast.
Three-quarters of the way in, the novel suddenly becomes a page-turning murder mystery with a gratifyingly complex plot, a dizzying Usual Suspects-style narrative with nods to detective novelists conventional (Agatha Christie) and unconventional (Carlo Emilio Gadda).
With a companionable heroine in Irene, and a satisfyingly complex plot, The Invisible Library – the first of a series – is a book in which to wallow.
In a deliciously complex plot, he gives us everything from an autistic savant witnessing a murder and then being unable to communicate what he has seen, to Salander audaciously and ingeniously (as ever) hacking into the NSA.
But a kidnapping might well contribute to a more complex plot.
