The fifth episode of Masterpiece: The Forsytes, titled "The Forsyte", saw Frances and Jo's marriage begin to crumble due to family tensions. Frances became suspicious of Jo's connection to Louisa (Eleanor Tomlinson) and the illegitimate children he has by her, believing he was manipulated by her. She took action against Louisa to protect her marriage, but Jo refused to comply. The episode also featured a breakdown in Jo's relationship with Louisa and their children. The tension escalated as dark impulses of certain family members took over, creating divisions that threaten to destroy the fragile bonds of the ForsyTe family. Actress Tuppence Middleton and costar Danny Griffen explained that their relationship was carefully crafted to make it more impactful.