Problem with my 88 Civic

Ok, I have an original 1.5L motor in my 88 Civic DX. Within the last few days I have had trouble with the far right spark plug wire. It would pop slightly out of suction until yesterday, when it actually popped out of the plug whole entirely. There seems to be air flow coming up through that hole but not the others and the plug wire won't stay in the whole.

My brother in law said it might be the gaskets gone out casuing an air leak but I thought I'd ask here. Any help would be great, especially since I depend on this car to get to work and school.