After 4 years, 81 cases and a near-death experience, Officer Kate Beckett (Stana Katic) finally got emotionally in sync with bestselling author Richard Castle (Nathan Fillion). But they had to face the reality that there was an unwritten rule in the New York Police Department: colleagues were not allowed to fall in love. How to hide the sweetness of the two became more difficult in the later plot. Castle abducted Beckett to his Hampshire villa on the weekend, thinking of a world of two people, but the murder case followed them everywhere. However, external factors are not the only source of problems that entangled them. Andrew said: "He is still the old boy who never grows up, and she is stubborn. They still have a lot of things to get along with each other, and there are many little secrets to be confessed bit by bit."