Tarzan and the Forbidden City: (#20) delves into the thrilling adventure of Tarzan, whose bond of friendship with Brian Gregory compels him to aid an expedition despite his initial indifference towards the adventurer’s fate. Guided by Paul d’Arnot, Tarzan sets out to rescue Gregory and his sister from their perilous journey drawn by the legendary city of Ashair and the mythical Father of Diamonds – the world’s largest gemstone. Meanwhile, the enigmatic Atan Thome harbors a personal vendetta against the diamond and orchestrates espionage and sabotage among the expedition members. The story culminates as both parties reach the remote and mysterious Ashair, only to find themselves ensnared in the city’s cruel and deadly rituals.