Metastasis — the spread of cancer from a primary to a distant secondary location — is implicated in over 90% of all cancer related deaths. Despite its importance in patient outcome, a full understanding of the metastatic process remains elusive, largely because of the difficulty in studying the phenomenon experimentally. Recent experimental evidence — including the discovery of the so-called ‘pre-metastatic niche’ — has suggested that metastasis may be a more precisely controlled process than previously thought. In particular, it has been suggested that a developing tumor may be able to corrupt, or ‘educate’, infiltrating immune cells and have them switch from cytotoxic to tumor-promoting roles. Such ‘tumor educated’ immune cells can then travel to distant sites and establish favorable conditions for the settlement and growth of circulating tumor cells. In order to investigate the consequences of tumor-mediated immune education on metastatic spread and growth, we have developed an ordinary differential equation model for tumor-immune dynamics in the metastatic context. The model is studied analytically and numerically, with an examination of the effects of tumor education of immune cells on metastatic dormancy and metastatic blow-up.