This paper presents a new theory of professional socialization in relation to diploma of higher education in nursing students (Project 2000). It was derived from a 3-year, grounded theory, longitudinal study exploring the effects of supernumerary status and mentorship on students undertaking practice placements. A purposive sample of 17 students was used. Ten students volunteered to be interviewed on five separate occasions throughout their course and to keep a diary to record their experiences of mentorship during their practice placements. Their diary acted as an aide memoir during their tape-recorded interviews. The other seven students participated by diary only and kept written accounts of their experiences of being supernumerary and having a mentor whilst on practice placements. Data were analysed with the aid of NUD.IST and subjected to the constant comparative method of analysis. Findings indicate that the mentor is the linchpin of the students' experience and that some students develop intuition much earlier than previous work has stated.