After their mother dies, Bo convinces estranged brother Duncan to join him on a canoe trip down the Missouri River. Bo is unaware that the only reason Duncan accepts his invitation is because he needs a place to hide from the Chicago gangsters to whom he owes money. The brothers — Bo the golden child and Duncan the black sheep — try to repair their frayed bonds as they navigate the Missouri, which they paddled as boys, alternately fighting and forgiving as they retrace the route. But what happens on the trip will not only decide the fate of the brothers’ relationship — it will perhaps determine the course of their lives. “The Big Muddy” — part of SLIFF’s annual Show-Me Cinema program — was shot along the river between Columbia and St. Joseph, Mo.