Complex sentence: The plot is to ambush a truck containing a cargo of diamonds as it makes its way down Leopard Street; but heavy security means recruiting a larger criminal gang than usual, and inexperienced newcomers threaten to derail the scheme.
Split into simpler sentences: The plot is to ambush a truck containing a cargo of diamonds as it makes its way down Leopard Street. But the heavy security means recruiting a larger criminal gang than usual, and inexperienced newcomers threaten to derail the scheme.