Faith of a Patriot

PREMISE: An important world leader is being targeted for assassination and the player's Adepts find themselves caught up in the action. They must work to flush out the would-be assassin, along with whoever might be helping them, and discover what is motivating the killer(s). 
THEME: Political intrigue, danger and racing against the clock are the main themes of this type of story. Player's Adepts will also probably have to deal with the political friction of different parties; for instance if the president they are trying to save is Democratic, they might not find any avowed Republican to be too helpful (or the other way around). 
CONFLICT: Who is the killer, what does he plan to do, why is he doing this? Players will have to chase down suspects and set traps, interrogate possible suspects or accomplices and pour through military and political files in order to get to the truth. And that's all in addition to having to protect a world leader, a man or woman who spends much of their time traveling and meeting other world leaders (not a good lifestyle if other people need to protect you).
Psychopaths tend to talk and brag, so for the beginning of the story you could have the players follow a paper trail as the assassin actually contacts authorities to alert them to his deadly designs. If the killer has allies (or bosses, especially foreign governments or mega-corporations hostile to the targeted politician) the player's Adepts might run into armed muscle along the way, mysterious ex-military dudes who will try to stop or kill them in order to protect the assassin.
Finally there is the assassin himself: if he is a Supernatural you should make him a tough and strong one, able to take on most members of the Squad and hold his own. 
RESOLUTION: There are several different ways you can play this story. In the first one, the player's Adepts are so good at what they do, they actually locate and arrest the would-be assassin before he even makes the assassination attempt. If you feel like being stubborn (or just cruel as a Storyteller) you can reveal to the players that he was just a patsy and that a larger conspiracy is at hand (there might even be a backup assassin in waiting!).
Secondly, if the assassin makes the attempt but the players foil his plan and the target lives, this may open up further stories as the player's Adepts must now uncover whoever was aiding the assassin. If the players captured the assassin but failed to save the target, they can still continue to investigate, but law enforcement and politicians may not trust them due to their failure to stop the assassination in the first place.
Thirdly, if your players whip out the brain-juice and concoct a truly spectacular solution to the problem (they use their abilities to set up a perfect replicate of the targeted world leader in order to act as a dummy, they arrange for multiple speaking events at the same time so the killer can't possibly know which one to be at, etc.) and manage to catch the killer, than the Storyteller should reward them generously for a job well done.
Finally, the Storyteller could save an important plot twist for the very end - the assassin was actually one of the good guys and the target is, in fact, a Supernatural and an agent of the Darkness!