South Park: The Stick of Truth -
Use Nagasaki to open the way. Keep modulating the spell until the wall starts to tremble. Then, keep holding it, until it cracks. You will now need to match up against the entire wildlife of Canada. The Power Potion, in combination with some strongest AoE ability, e.g. Jimmy's Brown Note should be able to deal with them very quickly. Free the minister of Montreal and he will translate the letter for you. Finally, you can return to South Park. To get there, you need to go South in the forest. Go to Annie and to Kyle, after that.