Damp Squib

Gunpowder, treason and plot. Or if you are a fan of CSI - means, motive and opportunity. But then again relying on gunpowder of dubious quality and the even more unlikely hope that having ignited the king and parliament, you'd then spark off a revolution and reinstate the church of Rome, bet they'd have done it better in Hollywood...
Catesby would no doubt have been a dark and romantic figure with a gift for oratory who convinced people that his cause was just, James I would have been an evil figure, presumably complete with white persian cat (for some reason a necessary accessory for villains) and the members of parliament cast as oppressors of the common people and deserving to be blown into lots of little pieces.