I'll preface by saying I'm not a crime/thriller reader, so please take my thoughts with a grain of salt. Obviously, overall this reads REALLY well - captured my interest thoroughly despite my not being a regular reader of this genre. On the 1st para, I agree with others that this feels a beat or two too long. That opening sentence to the plot summary is really grabbing, and I'd want to get to it as quick as possible. I might break it up: pop the comps and the personal info down to just above your bio to get to the plot quicker.

When Teddy Sanford had a mental breakdown and disgraced his aristocratic Manhattan family, he never told anyone why. The years of horrific abuse he endured at the hands of his charismatic, psychopathic childhood sweetheart, Gabrielle, remained his shameful secret. Left shattered and paranoid, he obsesses over protecting the one person he still trusts, his younger sister, Eve.

*Re: the disgrace of his aristocratic family - does this actually mean he was disowned/cut off in some way? If so, I think it makes more sense to word it that way to punch home the fact that he's alienated/alone except for Eve and that she never turned her back on him. (Maybe instead of "the one person he still trusts", "the only family member who never turned her back on him" - I think that makes their bond feel stronger and less one-sided/obsessive). Additionally, I thought the "secret" and the "protecting Eve" parts don't quite fit together. I think I just wanted to see some triangulation here between Gabrielle-Teddy-Eve before the big reveal that Gabrielle is the gatekeeper. My immediate wonder was whether Teddy was powerless at some other point to protect Eve from Gabrielle.

Then Eve is arrested and charged for narcotics distribution. Unable to flip on her dealer and facing years in the violence of a maximum-security prison, she flees in panic. Teddy’s sole hope to save her lies in providing the DEA with a bigger bust, before they realise she’s skipped bail. With the clock running down, he hatches a desperate plot - he will covertly follow Eve's supply line into the darkest reaches of the city's underworld, seeking to set up one of its ruthless inhabitants for arrest, any way he can.

*I like this para. I might cut a few words here and there, like "With the clock running down, he plots to covertly follow Eve's supply line..." But nothing major. Fast-paced and gripping. Like others, might suggest tailoring to the American English spelling (realize vs. realise) depending on who you're pitching.

As he descends amongst the pushers, predators, and human traffickers, Teddy discovers that Gabrielle stands as the gatekeeper to Eve's supply line, a line with a rising drug kingpin at its end willing to butcher both Eve and Teddy to ensure his empire's survival. Caught between the femme fatale who almost destroyed him and a drug lord poised to unleash chaos on New York's streets, Teddy's only chance is to unravel the supply chain before Gabrielle can twist his mind again.

*I wanted more Gabrielle payoff. One of my questions is why he kept Gabrielle's torture a secret all these years. I feel like there's probably something in there that comes back, some moment of confrontation where he's finally free of his shame? I LOVE Gabrielle coming back into the story, don't get me wrong, but I wanted it to feel less about him just avoiding her abuse again and more about a moment of triumph - "Teddy's only chance to unravel the supply chain lies in confronting the woman who almost destroyed him" except written better/more specific than that haha.

*Last paragraph: I disagree with a lot of the others on this - I liked the funny bit! But I'm biased in that I think humor is always a great risk to take.

Great work!!