Well, first, the cook is an apprentice in London. He gets distracted by the city's nightlife and gambling. His work suffers as a result. His master warns him a few times, but he doesn't listen. Eventually, his master fires him. That's the main sequence of events in the 'Cook's Tale'.
In the 'Cook's Tale', the key events start with the young cook being apprenticed. He then starts to engage in activities like gambling and partying instead of focusing on his cooking duties. His master observes his wayward behavior and tries to correct him. However, the cook continues with his irresponsible ways. Finally, his master, having had enough, dismisses the cook from his service. This series of events showcases the consequences of not taking one's responsibilities seriously in a medieval work - related context.