The Loop by Ben Oliver

An AI controlled prison is inescapable for the teenagers inside it. There's no contact with the outside world, but rumours still filter through - and those rumours are very dark.

Some time in the future - at least a hundred years from now, it's possible I missed a more exact timeframe - the world has fallen under the power of the One World Government and an AI called Happy. Happy controls everything, everywhere. Including the Loop and Block prisons, one for under eighteens, one for adults. Luka's been in the tightly regimented, isolating Loop for several years when things start going wrong. If Luka is careful, if he's clever and quick, if he chooses his companions wisely, he may just survive. But if not...there are far worse things than the Loop in the world...

This is a terrifying, far too plausible look at a possible future. The Loop is inescapable, and isn't that good for dangerous criminals? Happy has found a way to extract energy from the prisoners to help power the prison; isn't that poetic justice, making them part of the system? The med tech keeping them prisoner, the dangerous medical trials they can choose to undertake, it all makes so much sense. That's the most terrifying part of it. And the ending is awful, a real proper cliffhanger.

Even without the futuristic parts, there are some genuinely scary scenes - rats, anyone? - and I really enjoyed this read.

Life inside The Loop-the futuristic death row for teens under eighteen-is one long repetitive purgatory. But when news of the encroaching chaos in the outside world reaches the inmates and disorder begins to strike, the prison becomes the least of their worries. Perfect for fans of The Fifth Wave and The Darkest Minds.

It's Luka Kane's sixteenth birthday and he's been inside The Loop for over two years. Every inmate is serving a death sentence with the option to push back their execution date by six months if they opt into "Delays", scientific and medical experiments for the benefit of the elite in the outside world.
But rumors of a war on the outside are spreading amongst the inmates, and before they know it, their tortuous routine becomes disrupted. The government issued rain stops falling. Strange things are happening to the guards. And it's not long until the inmates are left alone inside the prison.

Were the chains that shackled Luka to his cell the only instruments left to keep him safe? In a thrilling shift, he must overcome fellow prisoners hell-bent on killing him, the warden losing her mind, the rabid rats in the train tunnels, and a population turned into murderous monsters to try and break out of The Loop, save his family, and discover who is responsible for the chaos that has been inflicted upon the world.