A Dual‐Metal‐Catalyzed Sequential Cascade Reaction in an Engineered Protein Cage**

Herein, we describe the creation of an artificial protein cage housing a dual-metal-tagged guest that catalyzes linear, two-step sequential cascade reaction. The consists fusion HaloTag and monomeric rhizavidin. Inside capsid, established ruthenium-catalyzed allylcarbamate deprotection reaction followed by gold-catalyzed ring-closing hydroamination led to indoles phenanthridines with overall yield up 66 % in aqueous solutions. Furthermore, show encapsulation stabilizes metal catalysts against deactivation air, proteins cell lysate.