Excursion ending at nightfall (3,4)
I believe the answer is:
day trip
'excursion' is the definition.
(I've seen this before)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for day trip that I've seen before include "Outing" , "Excursion within 24 hours" , "Brief excursion" , "Pay dirt (anag.)" .)