Prologue=Beginning of the story, like Gran Turismo 5-Prologue

Epilogue-End of the story

I bet Mile High Club is when 'Soap' is in hospital and he's having a dream, this mission will be the beginning to COD 5. You will wake up and be lying in a hospital bed after dreaming about the mission, then recover and get back to action. There'll be another character in the game like Jackson in COD 4