Begin the "Abbey Tower" level and immediately walk out to the left from the corridor you are standing in. Look for an old wooden cart against the side of the building. Destroy the cart, and there will be a fallen comrade on the ground underneath the debris whom has a note attached. Pick up the note. It makes reference to his sister Laverne and brother Bernard, and it is signed by "H.", which refers to the other main character known as Hoagie.