Mischief is behaviour that is intended to cause trouble for people. It can also refer to the trouble that is caused. The more sinister explanation is that he is about to make mischief in the Middle East again
{i} naughty behavior that is not spiteful; source of evil or misfortune; harm, damage; trouble maker (usually a child); vexation, annoyance; one who has an annoying disposition
disarrangement of order; trouble or vexation caused by human agency or by some living being, intentionally or not; often, calamity, mishap; trivial evil caused by thoughtlessness, or in sport
Mischief is playing harmless tricks on people or doing things you are not supposed to do. It can also refer to the desire to do this. The little lad was a real handful. He was always up to mischief His eyes were full of mischief