maeve and randy were having an affair which is why randy had the idea for this trip , dave caught them but randy got away , the mystery box was maeves suitcase in which she had packed all her sequined cruise clothes to run away with randy , randy had to get rid of the suitcase and made the phone call to arrange for someone to pick it up , dave caught him and killed him and took the suitcase and buried it under an old oak in the woods . ''