Reese's nine-year-old sister is predictably adorable. She'd probably even come across as cheesy if Lockdown weren't such a grim book. As it stands, though, she's a much-needed ray of sunshine in an otherwise bleak landscape. And she serves as a sort of beacon for Reese—a way for him to look to the future with a sense of purpose instead of abject depression.
From Icy's conversations with her big brother (she visits him in jail, and they speak on the phone twice), we know that she has big dreams. At first, they know no limit: She wants to go to college, to win an Oscar, and be the first woman president. But even at age nine, doubt is starting to creep in. "I probably won't be able to go to college" (28.35), she tells Reese; "Not a lot of people from our block go to college" (28.37). While this depresses the heck out of Shmoop, it strengthens Reese's resolve to be there for her. He tells her he'll pay for school, and she says she'll go to Princeton.
With the help of her big brother, Icy's still dreaming by the end of the book. When we check in on her a year after Reese's release, she seems to have some heavy responsibilities—"It's almost like Icy is the woman of the house" (35.5), Reese says. But she hasn't lost her capacity for hope: "Icy believes in herself big-time, and you can see it when she talks about going to college and becoming a teacher or a lawyer" (35.12). Go, girl.