After Sulli left the class, Krystal and Zelo were chatting at their place while eating ice-cream.     "Noona, are you free after school?" Zelo asked.   "I think so. There're no projects to do today", she answered as she finished off her ice cream.   "Since you're free, would you like to watch movie with me tonight? I heard 'G.I Joe: Retaliation' is really good"   "Okay. I'm free today anyway" she said then continued, "I've been always wanted to watch G.I Joe: Retaliation since it came out. I'm looking forward to it~~~"    "So noona, are you okay if I pick you up at your house around 7 pm?"   "No prob---"    A phone ring interrupted their conversation.   "Yoboseyeo" Krystal answered her phone.   "Soojung ah, it's me, Yonghwa oppa"   "De, oppa"   "My friend, Siwon's brother is coming back to Korea today and he's going to stay at our house. Siwon told me that he gave his bro the house address and the passcode. So cancel your plans for today and go back home early, arraso?"   "De...." she replied with a sad tone, then she asked him, "When'll you come home, oppa?"   "My last patient's booking is at 4:50 so I think I'll be back around 6. Soojung ah, I have an operation to go so I'll hang up now. Have a nice day, Soojungie"   "De. Oppa too. Have a nice day"   Then she hung up with a sigh and turned to Zelo who's staring at her curiously.   "Zelo ah, Mian! Yong oppa said today there'll be a guest at ou