How to use mongoose findOne

I have the below schema (apologies that it is in coffeescript)

Schema = mongoose.Schema

AuthS = new Schema
    auth:   {type: String, unique: true}
    nick:   String
    time:   Date
Auth = mongoose.model 'Auth', AuthS

I simply want to recover one record which is definitely in my database:

Auth.findOne({nick: 'noname'}, function(obj) { console.log(obj); });

Unfortunately this always logs null. db.auths.findOne({nick: 'noname'}) in mongo shell always returns a value. What is going on?