This article describes a case study of a new venture by the children's theatre company Oily Cart to develop a participatory theatre piece for carers and their under-two-year-olds, entitled Clouds. Given what little is known about how to design and conduct arts events with this age phase, a case study offered the opportunity to identify features and factors which might then pertain to other, similar ventures. At a time of rapid expansion in arts opportunities for the very young, it is important to move beyond the usual evaluation procedures to research such arts occasions in more depth. The study adopted the usual case study design of collecting data from many, varied sources including documentation, observations of performances, interviews and direct participation. Although orientated by some initial guiding questions, the study remained open to foci as they emerged. In particular the reseacher became interested in the nature of the experience for the very young children and their carers. This, in turn, threw attention onto those factors which facilitated the participation of very young children--the design of the theatre piece and, importantly, the facilitative skills of the actors in improvising the playful sequence of episodes. One of the conclusions to emerge is that theatre for very young children requires specific and additional sets of skills from writer, designer and composer and from the participating actors, which, with Oily Cart, have evolved from considerable experience. The specific skills of the improvising 'inter-actors' with the child-adult dyads emerged as crucial and central. The study also drew attention to the demands on adult carers to become participatory players. While finding that the majority of carers adapted to the experience willingly, easily and enjoyably, some found the participatory role less comfortable. Some possible reasons for this are explored.