The phrase "according to the synopsis" is correct and usable in written English.
You can use it when referencing information or details that are derived from a summary or overview of a text, film, or other work.
Example: "According to the synopsis, the main character embarks on a journey of self-discovery."
Alternatives: "as stated in the synopsis" or "per the synopsis".
According to the synopsis, The Glamshack is an intense love story.
According to the synopsis, mankind is gradually losing its ability to use everyday technology.
This time round, Machete is recruited by the US president for a mission that, according to the synopsis, "would be impossible for any mortal man".
Math is on my mind today, thanks to a tweet by Roger Ebert linking to an article in Scientific American by the physicist Mario Livio, which, according to the synopsis, asks whether mathematics is an invention (a creation of the human mind) or a discovery (something that exists independently of us).
Many of the man-made ponds for storing toxic sludge from coal mining operations have dangerously weak walls because of poor construction methods, according to the synopsis of a study for the Office of Surface Mining Reclamation and Enforcement obtained by The Washington Post.
The Interior Department's mining agency ordered the survey — which is in draft form and has not been publicly released — after its engineers noticed that companies were using coarse refuse that will not stay compacted except "within a narrow range" of moisture conditions, according to the synopsis.
Set in the Scottish highlands, the film concerns flame-haired archer princess Merida (voiced by Kelly Macdonald), who according to the official synopsis "confronts tradition, destiny and the fiercest of beasts... to carve her own path in life".
The book, published last year by Random House India, follows Ayesha who tries to juggle her often dangerous job with her search for a husband but, according to the official synopsis, her most pressing problem is "how to straighten her hair during the chronic power outages".
Directed by Anna Boden and Ryan Fleck, "Captain Marvel" will follow fighter pilot Danvers "as she becomes one of the universe's most powerful heroes when Earth is caught in the middle of a galactic war between two alien races," according to the official synopsis. .
In response to mysterious distress signals, according to the show synopsis, Earth launches its first manned rocket to Mars and encounters a race of Amazon vampires with a thirst for human blood, led by the beautiful and evil Queen Voluptua (played by Brooke Lewis).
According to the publisher's synopsis of Revolution he lays out "a vision for a fairer, sexier society that's fun and inclusive".
