The below description is taken from LEGO.com.
“I’ve got bad news, and more bad news…”
Poor Banshee. It’s not her fault that her job is to warn people about bad news in their future. And she does it very well, with all of the woeful weeping and wailing that you might expect from an ancient spirit of ill omen. But nobody likes to hear her tidings of misfortune, and so she finds herself unwelcome wherever where she goes.
It’s hard to make friends when you’re compelled to inform your fellow Minifigures that they’re going to stub their toes, or misplace their phones, or forget to water their plants. It’s not like the Banshee causes the problems herself; she’s just cursed with the ability to see that they’re going to happen. For some reason, though, everybody seems to blame her anyway. On the bright side, she’s recently become pen pals with the Sad Clown, who just loves getting bad news!