After two decades of post-apocalyptic love, it soon became clear the two were soulmates as they decided to live out the rest of their days together in Massachusetts.
However, things took a tragic turn after Frank’s health took an upset downward spiral as he became terminally ill.
Frank asked Bill to end his suffering by giving him a drug overdose and while he agreed to do so, Bill also took an overdose so they could die together.
Although their lives came to a heartbreaking end, Bill left an emotional letter for Joel, as he explained Frank had given his life new meaning.
The Last of Us continues Sundays on HBO in the US and available in the UK on NOW TV the following Monday.