Roosevelt Island Promenade Walkthrough Part 7
Blackwell Unbound Walkthroughs & Videos
Johnny Ivory's & Isaac Brown's Duet
Once you have finished your conversation with Joseph Mitchell, head back to Johnny Ivory's and talk to Cecil. As soon as you mention Isaac's sister, however, he tells you it's time for you to leave. This is when you need to swtich to Joey. Once you have switched to Joey, just click on Cecil and Joey will mention that it seems Cecil is hung up on a woman.
Now is the time to switch back to Lauren and ask Cecil about Love. This will get you the information you need. He'll tell you her name was Sarah, and you'll get a bit of information out of him on that topic if you ask a few times. When you reach the end of his responses regarding Sarah, ask him about Isaac again.
This is the line of questioning you want to follow until he tells you about a duet Isaac and his sister used to play at the end of thier gigs. He'll even play it for you. This is what you need. Have him play it again, and use the Dictaphone on Cecil to record the music.