In the present paper, we investigate the Herculaneum Conservation Project (HCP), a partnership agreement between one public and two non-profit actors aimed at improving the conservation of the archeological site of Herculaneum. The study is motivated by different elements of interests. First, although HCP has been defined by UNESCO as a significant case study for private-public partnership (PPP) in the cultural heritage sector, its financial and organizational aspects are still under-investigated. Second, and quite paradoxically, an analysis of HCP through the lenses of PPP literature reveals its distinctive nature-i.e. more a borderline case than a typical example of PPP. Third, the presence of a similar archeological site nearby Herculaneum-i.e. Pompeii, also defined as a Herculaneum sister city-allows a thorough assessment of the benefit of the partnership scheme in a counterfactual logic. Through the study, we complement the current debate on partnerships in the heritage field, we report on an atypical experience of partnership, and we problematize the rationale of this governance solution within the Italian public sector.