The Beat Of The Wolf's Dying Heart

It is not far in the future, but the world has changed out of all recognition.
The climate has changed and the warming means that wild animals have moved from the equator into the northern climes. Humanity has had to retreat to Protected Settlements and cities surrounded by massive walls.
Still, Artidical Intelligence has taken over all means of production, from mining to manufacture, as well as the production of food. This is delivered to all centres of population through the Tubes, overhead mag lev trains in enclosed, transparent tubes that criss-cross the country, allowing high speed communication and delivery. The system has been perfect for many years. When it starts to go wrong, it's as surprising as it is devastating and life threatening.
But most people have lost the will to live. With all their needs supplied, why should they worry? Surely the invisible 'government' will sort out the problems? Only a select few, the Agents, know that such a structure no longer exists. If individuals can't work together, combine their efforts and talents, then what is left of the population will soon fade away.
It's a turning point in the history of the world, and the stakes have never been higher.
Of course, the animals don't care about this struggle: they still have viable habitats. And the planet doesn't mind. It will continue, whether or not human beings are on board.