This is the 11828th most frequent Polish word.
kończyć
To finish or to end.
Here 'kończyć' implies the action of coming to the end of an activity, specifically here referring to finishing the task of preparing dinner.
Zaczynam kończyć przygotowywać obiad.
I am starting to finish preparing dinner.
'Kończyć' expresses the commitment or determination to bring a task (the project) to completion.
Skończę ten projekt do jutra.
I will finish this project by tomorrow.
In this sentence, 'kończyć' is used reflexively to describe the cessation or conclusion of an event (the TV series).