Spoiler alert!!!
So apparently ki tae has been sleeping in his company office bc his ex suddenly showed up ( the crazy ex that became the reason ki tae and ji woo met ). his ex was having some financial problems and couldnt find a place to stay... he had some issues with his family i think and he was being bugged by reporters. anyway, fast forward, ji woo decides to visit ki tae s apartment trying to wonder what ki tae was hiding or why he was being so secretive. when he rings the bell, the ex appears at the door... and ji woo tries to keep his cool and finds that ki tae isnt at home. he tries to call ki tae but ki tae s phone was switched off as he dozed off in his company office. ji woo continues to work in the new cafe, ki tae tried reaching ji woo but ji woo didnt answer any of his calls. suddenly ki tae remembers the cafe ji woo was talking abt for work and decides to check whether ji woo would be there. he disguised himself, with a mask trying to hide his identity as ji woo served the customers and ki tae. ji woo already knew it was ki tae and exposes him after ki tae waited there for the cafe to empty and close up. ji woo asks for an explanation and ki tae explains everything. ji woo understands and doesnt get irrationally mad— they make up, the ex leaves the house and they start living together.
The end!

Somebody spoilee me?