‘At the end’ and ‘in the end’ are a logistical nightmare for most students – and that’s completely understandable. One preposition out of place and it’s all wrong. Here’s an explanation to help you.
‘At the end’ is something that is located in time or space. So, in our example, the house is located at the end of the street, because you are talking about a physical location. It works with time too, where something happens, not at the beginning, or in the middle, but in the final moments. So, for example, you can say something like, “At the end of the film, Gladiator was killed.”
‘In the end’ is about the result, what finally happened. If you and a friend are deciding where to go and then finally, you stay at home, you can say, “We talked about going to the pub, but in the end, we stayed at home.”
So, the two phrases together: At the end of the movie, the man and woman got married. So, in the end, it was a happy film.