The lecture reports of the archaeological project at Shalfak, one of two surviving Middles Kingdom fortresses in Lower Nubia. After the site had seen a summary investigation by the Harvard University and Museum of Fine Arts Boston Expedition in a single season in 1931, it remained untouched until it was thought to have been drowned in the waters of Lake Nasser/Nubia in the 1960s. Only in 2002 it transpired that Shalfak and the neighbouring fortress of Uronarti had survived on small islands in the reservoir lake, some fifty kilometres south of the Egyptian-Sudanese border. Funding of the Egypt Exploration Society was instrumental to set up the Shalfak Archaeological Mission (SAM) in the harsh conditions of this environment in 2017. The talk will introduce both the site and the current fieldwork.