in an iterview for example in ielts speaking exam when you are being asked about a movie or a novel in which tense we are suppose to retell the story : past tense or present tense
You can do either - but keep to the one tense throughout.
You may use either, but the present tense is generally more engaging, or exciting. Some, however, will disagree. I believe that being consistant in the tense is imporant, and then it's how you tell the story.
The thing to avoid is mixing tenses: He comes to an abrupt stop and looks into his rear view mirror and saw the police lights flashing. That is clearly wrong. It is no wonder the Language Police were chasing him!