Rise of the Machines
One possible scenario that AI could pursue, if you believe Hollywood and the sensationalists, which I don't. I think that AI and humanity will share the same goals and hence ultimately work together, but who really knows?
The plot isn't super complicated, we have a war raging between the AI lead machines and humanity in the future. The AI controlled machines find a way to send a cyborg back in time with one mission. The mission is to kill the mother of the resistance leader.
The resistance is also able to send one man back to protect her from the cyborg, known as a "Terminator". The soldier must ensure that she lives no matter what the cost. The Terminator of course is a machine, it does not stop, can not be reasoned with and only has one goal to achieve, no matter what the cost.
As this was a big budget Hollywood movie, the special effects are what you would expect, as well as the ending, the good guys win, Sarah lives, but neither the soldier or the Terminator. Basically enjoy the action, the special effects, and don't look at the plot too closely.