This dissertation examines the informal peer mentoring relationship of a first-year teacher and an experienced teacher. Teacher preparation, struggles of first-year teachers, and problems relating to teacher retention frame the hard and the heart of this study. This qualitative descriptive case study was guided by the following research question: How does an informal peer mentoring relationship mutually benefit the professional development of a first-year teacher and a veteran teacher? Data sets were collected from transcriptions of face-to-face meetings, mentee written reflections, mentor written reflections, and posts on EdModo, a secure social network for teachers. Three themes emerged from the data analysis – ethics, knowledge, and reciprocity. This case study contributes to the growing body of literature on mentoring by demonstrating the personal value of a mentoring relationship, the complexity of the job of teaching, and the dynamics of one specific informal peer mentoring relationship with a first-year teacher and an experienced teacher. The results suggest the need for more qualitative research examining the dynamics of informal peer mentoring relationships in multiple contexts.