CSCL software tools must provide support for group work and should be based on a collaborative learning technique. The PBL based CCCuento tool is introduced here. It is intended to support apprentices groups in the collaborative creation of stories in order to improve language use and development of writing skills. The tool follows a model, which includes several positive interdependencies and is implemented as a sequence of individual activities followed by break periods. The break periods are used for reviewing and discussion. An experiment is reported in which several groups of high school students used the tool.