Leonardo - Season 1 Episode 7 Time Waits

After a Swiss clock-maker bringing a pocket watch to Piero drowns Leonardo finds the watch and discovers that it is magic and that it runs backwards,enabling the user to travel back in time. Machiavelli makes a copy which he tries to auction and this comes in useful when a gang of heavies pursue Leonardo for the real thing,which he is able to return to its maker's mother so that she can see her son again.