"Charlie Chan's Secret" (1936) is unique. Its predecessor is "Charlie Chan in Shanghai" (1935)---which featured Keye Luke in his usual role as Number One Son. All the remaining Warner Oland films in the series up to his final entry, "Charlie Chan at Monte Carlo" (1938), also had Keye Luke in the cast. However, "Charlie Chan's Secret", as others have pointed out, does not have Keye Luke on board. Rather, his "place" was taken (sort of) by the comic British actor, Herbert Mundin. Why did Keye Luke not appear in this film? Everyone seems to have missed him.
In the new DVD of "Charlie Chan's Secret", the extended commentary on the film fails to explain the cause of Keye Luke's absence-----only the fact that he does not show up in the film.
Is it possible that Keye Luke's void could be due to the fact that he was loaned by Twentieth Century Fox to M-G-M Studio around the same time to appear in the small but pivotal supporting role as Paul Muni's son in the classic Pearl Buck epic "The Good Earth" (1937)? Such loan out arrangements were not uncommon between studios in this period.
In any event, "Charlie Chan's Secret" survives his absence very nicely and emerges as a solid entry in the series with its own particular charm and entertainment value. But it does illustrate how the chemistry between Warner Oland and Keye Luke was very special and without doubt one of the greatest strengths of the "Charlie Chan" films.
