Buona notte al secchio
This colloquial phrase, typical of the Roman dialect, conveys disbelief and resignation. A fitting conceptual equivalence can be found in the English expressions: and that's it! / and that's that! / let's not talk about it anymore. An even more informal translation would be: yeah, right!.The allusion is probably to some bucket that fell into a well after its chain broke. No chance to get it back to the surface anytime soon!