It's a novel for children of 9-11 (I'm guessing.)
Kip Cusack and the Spy Formation League: Synopsis
KIP CUSAK AND THE SPY FORMATION LEAGUE is the first adventure of 12-year-old KIP whose world flips upside down when he finds that his ‘Support For Learning’ sessions are in fact a cover for a spy training network – the Spy Formation League. Not content with making him grapple with his spelling, life now seems to expect him to grapple with villains too!
Kip arrives home one day to find the contents of his GRANDA TOM’s potting shed being hurled into the back lane, and Granda Tom
When Kip meets IRWIN, his new SFL [explain] teacher, it’s clear she’s got more on her mind than trying to deal with dyslexia. She’s there, she claims, to mould the group
Kip’s first botched attempt to stalk the seed-pirates ends up with his incarceration in the Seedbanks [need apostrophe] freezers. But he has been practicing [UK spelling: practising] some of his spy skills – honest – and uses them to escape as well as to uncover the identity of one of SPORE’s top operatives, POULSON. What’s more, his adventure alerts Granda Tom to his grandson’s new identity – and prompts the revelation that he too was part of the SFL in his youth. With Granda Tom on board, the race to uncover the details of SPORE’s plans and rescue Taru careers onwards apace [don't like that phrase] but also brings new dangers.
Overhearing plans that SPORE are on the verge of completing their stranglehold on the seed supplies, and that Taru is also hidden somewhere on the island, Kip tries to signal for help… but when none arrives Kip knows he has no choice but to take on Patterson and Poulson
Kip, the SFL and Granda Tom speed back over to the island but there is one more shock in store. Not only are Patterson and Poulson intent on absconding with their haul [cliché and clunky!] but Patterson intends to
Gone are any traces of Kip’s former insecurities and indecision [first we've heard of this!]and
[I have no idea what this next bit actually means!] If only escaping the wrath of his mum was that easy.
Maybe now Kip can begin to grasp just what it might feel like to have the quiet confidence of his eccentric dad FERGAL. And maybe his adventure has given him a taste of what his mum has been trying to protect him from all his life. And he thinks he might be ready to taste more.
OK, here's what I think.
Essentially, it's a great synopsis, Louise! Lively, fast-paced, age-appropriate and credible. I disagree that there's a problem with vocab not matching the age-range. OK, so I perhaps know which phrases you're thinking of but this is the synopsis and not the actual story and it's very marginal. However, your concern about the sudden appearance of a new character at the end is valid. It definnitely feels wrong, not least because I have absolutely no idea how he fits. So, essentially, you've messed up the ending of your synopsis.
One important point: you mention the scene with Granda Tom's potting shed as though it's important. Actually, we never discover the point of that, so I think you've put it in for all the wrong reasons: it sounds quirky, fun and scene-setting; but it's not ultimately important or interesting.
I've also cut out some unnecessary words and details and tried to tighten your prose. That does give you room to add back in some action phrases to spark it up again but do so in a snappier way than the bits I chopped out.
Any other comments, anyone? Essentially this is how a synopsis should be just before the final revisions of it before sending out. You could get this perfect in another fifteen minutes of polishing.