MSD wiring question- search didnt help

i have a thin blue wire going from my MSD through the firewall and up near the steering column. I recently took off my dashboard and hooked up everything(or so i thought) and it cranks, but no spark . So i traced this wire from the box to the steering column, where it is clean and shiney , but attached only to air . Where does this little wire go to start my car? thanks in advance guys(and ladies)

i dont know which one to use on that, but thanks anyway. anyone know where this wire goes? its the only wire you MSD users had to run through the firewall