He ended up drunk because he came at Harry's house, saw Zoe (Su Yeon) there, and denied that she's Su Yeon he's looking for.
Now, he's drunk, and he wanted to sing at norebang (karaoke). But his friends fooled him, and gave a spoon as his microphone.
He sang, then his friend said that he got 100. So Jung Woo said that he's really a singer. =))
Cute, isn't it? :")