Any teacher knows the difficulty of getting students interested in learning, especially when they face emotional or economic challenges at home and bullying and failure at school. In the San Francisco public school with the highest incidence of disciplinary suspensions, the classroom is little more than a holding pen. But with a bell and hope, mindfulness teacher Megan Cowan offers tools the students can use to change their lives. At first her efforts seem futile in the face of so much derision and apathy. But slowly the students find the benefits, and mindfulness brings them self-control, hope, success and joy.