Down is a thief sent in to win the trust of Reynolds, another thief, and to work together to take down a big diamond score. Niven is the man trying to pull the strings.
I felt Reynolds and Down were good together, and had it just been a romance film, I would've been easier on it, but it kind of promises some Ocean's Eleven kind of hijinks, but the film stays pretty light on that stuff.
I notice a lot of Reynolds' films around this time try to coast on his charisma, but you just need more story sometimes.
I think it needed to show us more of these people stealing stuff than just tell us what they did in the past. At nearly two hours, it needed it to help move the film along better.