The Apothecary Diaries, Vol. 5 (Light Novel)

After breaking a 'curse' on the imperial heirs, a palace servant with training in herbal medicine is promoted up the ranks to food taster... and right into the thick of palace intrigue! 

The birth of Gyokuyou's son earns her the title of empress and rewrites court politics. Jinshi can also no longer continue his pretense as a eunuch at the rear palace. Although the Shi clan's demise restores peace, threats still loom - including an impending plague of insects. Maomao, as ever, finds herself caught up in new dangers. When Jinshi orders an expedition to Gyokuyou's homeland, Maomao heads west. But something is lurking in the shadows of the glittering city, and the apothecary must uncover it or face certain peril...