### Clue: Imprisoned old fellow given sentence before it's too late (2,3,4,2,4)
### Answer: IN THE NICK OF TIME 
 ### Explanation: Definition: before it's too late
 [IN THE NICK](in slang, to be in prison) + O(abbrev. for "old") + F(abbrev. for "fellow) + TIME(slang for a prison sentence).
Defn: …, just about.