It had been a week since the birth of Joshua Tyler Sloane and Addie had told them they could take him home today. As Mark headed to the nursery he bumped into Callie. She couldn't help but comment on the situation at hand. "So Sloane, its time for you to memorise your son's birthday because I bet in one years' time you will be walking the halls not realising the significance of the day, and Izzie ….well she will finally know what she has married and she is stuck with." Mark initially ignored the comment and walked by, but all of a sudden he stopped and turned to Callie saying "You know what Torres, you just can't stand the fact that Izzie and I are happy, have a beautiful little boy and have a perfect life... As Meredith would say McStunning and McSteamy have a McBaby and you are so McJealous." He walked away laughing, leaving Callie to ponder on what he just said. Without having walked more than ten paces he was greeted by Meredith who looked up at him and laughed saying "McSteamy is a McDaddy…….that is McWonderful." Mark put his hands to his hips saying "We have all gone nuts. Do you believe I was doing the Mc talk with Torres … me doing that? I am seriously a changed man." Meredith agreed and added "I am sure Iz wants to go home, so you better get going."

With that Mark walked to the nursery to get his little boy, but before he had a chance to open the door to the nursery he was pushed aside by a code team, who asked him to stay outside while they dealt with the situation at hand. Although a little frustrated he made his way to the parents lounge, but before he sat down his pager went off…when he looked down it was Addison. As he walked over to the nurses' station he turned his head and saw the commotion in the nursery was in fact over Josh. As he got closer to the window he found that his body had just gone numb – he couldn't move, but he knew he had to get in there. He saw Addie working furiously, and in a few moments she was walking towards him. She said "Mark" four times before he turned and looked at her. She grabbed hold of his arm and took him around the corner where there a lounge. She sat him down and as she took her scrub cap off she started by saying "Mark I am sorry but…" before she had the chance to finish he jumped in "Have we lost him?" She looked at him saying "No, no of course not. Not on my watch. I was about to say that I was sorry you had to see that." "What happened?" he asked as a tear slid down his face. Addie knew she couldn't sugar-coat the situation as she usually does with her patients. "Mark, Josh has Patent Ductus Arteriosus (PDA). I have called Burke for a consult, and I think it would be best if we corrected it with surgery straight away.." Mark was taken aback by this "what do you mean he has PDA?" Addie responded "Josh was born a little earlier than expected. So he was at risk of developing a complication. It just so happens that his large blood vessel (the ductus arteriosus) which was supposed to close at birth hasn't. I have tried the drug treatment and he responded well initially, but unfortunately it hasn't worked so surgery is needed".

"Wait just one second …. Are you telling me my son had a complication that you just happened to forget to mention to Izzie and me?" Addie sighed and said "No and yes" "What? What does no and yes mean?"" He yelled. Addie didn't respond, she just starred at the floor. With that Mark stood up one hand on hip, the pointing at Addie. "You know you have done something's in the past … but this … this just tops all of those off." He paused for a moment and than added "What exactly does that no and yes mean?" Addie stood up and said "Ask Izzie. I can't answer that question." With that she walked away. Mark had no idea what was referring to, so he turned and started running towards Izzie's room. When he got there, she was dressed, packed and ready to go. "Hey, where have you been?" she asked. "I have been sitting here waiting for you and Josh so that we can go home." Mark looked at her, she was glowing, and he couldn't believe that for a woman who had given birth only a week ago looked so perfect. He walked towards her and said "Before I say anything, I need to ask you something and I want the truth." She looked at his face... It was so serious and replied "What is it? Has something happened? Why don't you have Josh?" Mark went and sat on the bed with her. "Iz we can't take him home just yet. There is a slight complication." Izzie knew where this was going "It's about the PDS isn't it?" she asked. Mark jumped up and said "You knew … you knew and you didn't tell me?" "Mark please" Izzie said. "No, this is so not happening." Mark said. "Our son has to have surgery because of a condition you knew about, but you couldn't bother telling me about. What is this Isobel? What were you thinking off?" "Mark just listen for a minute." Izzie cried. At this point Mark was leaning forward on the wall. She went up to him and placed her arm on his back; he immediately turned around and said "At this moment, you have no right to touch me, Stevens." With that he stormed off, leaving Izzie alone in her room and in tears.

Izzie had made her way to the neo-natal unit, as Addison had moved Josh there after Burke had advised that the best way to move forward was surgery. As she walked in she saw Mark sitting next to Josh and for one moment she thought it would be better if she turned around and walked out, but Mark called over to her and as she walked over to him, he stood up and hugged her. "I am sorry Iz; I just went off at you without allowing you to say what you needed to tell me." Izzie kissed him on the cheek and replied "I should have told you, but Addison said it would heal itself in a few days and I didn't want to worry you. You had two major surgeries that you were stressed about and I didn't want to add to that. I am sorry Mark, I should have told you." "See Iz the thing that gets me, is that you thought you were well intentioned, but this is our son. If anything I should have pushed the surgeries aside and been with him. I trusted you when you said he was ok, when you knew he wasn't. This just shows me that you don't trust me." Izzie looked at him and replied "Mark off course I trust you, I love you." "Well if that's true, why hide the truth from me. Maybe Torres was right I will make a crap father." With that he pulled away from Izzie and left.

Izzie had no idea what to do. She knew in some ways she was wrong, but deep down she thought she was doing the right thing. She thought she was sparing him from something she was doing constantly – and that was panicking. With that in mind she sat next to Josh and started to talk to him. "Hey, baby. You know you and your dad are my world so any ideas you or your dad have of slipping away from me … well lets not have that." While Izzie was talking to him, she didn't realise that Mark had come back and was standing at the doorway, listening to her conversation. "You know I didn't want to tell your dad because that would scare him and I am scared enough for the both of us. You need one sane parent, and at the moment that's not me. You need to be ok, because I have to believe that we will all get through this."

As Izzie wiped away the tears, she turned around and saw Mark now sitting on the floor, with his back to the wall. His arms were resting on his knees, and his head lowered. She heard him sniffle, and knew he was hurting. She went over and sat next to him. As she put her arm around him, he turned and placed his head on her chest. He whispered to Izzie, "He will be ok right? …. We will be ok right? … Because I can't think of my life…." With out finishing his sentence Izzie kissed him on the head and said "I believe that Josh will be fine …. I believe that we will be fine …. We will survive this."