Episode Summary
Shen Qilan, pushed by her mother-in-law and husband, attempts to use Chu Ya to their advantage but ends up poisoning her. Jiangli saves Chu Ya, and Qilan's schemes are exposed. Abandoned by Jingxiu, Qilan commits suicide. Meanwhile, Jingming investigates a spy in Jingxiu's residence.

Spoiler Alert
"My Destined Consort" Episode 24: Drama, Deception, and Deadly Desserts!
So, things are getting spicy in the Lu household! Remember how Shen Qilan was all jealous and avoiding Chu Ya, worried she'd steal Lu Jingxiu's attention? Well, Mama Lu's now pushing Qilan to help Chu Ya and Jingxiu get together! Apparently, it's all about not letting the second branch of the family (Lu Jingming's side) get the upper hand. Chu Ya's basically the queen of Xizhou, and having her as an ally would seriously boost Jingxiu's chances of inheriting the whole shebang.
Speaking of Jingxiu, he lays it all out for Qilan – he's cool with sharing, as long as it means securing Chu Ya's support. Ouch! Qilan's heartbroken, realizing she's just a pawn in their game. But, being the resourceful woman she is, she decides to play along. She bribes a maid close to Shen Jiangli (Jingming's wife) and sets a trap.
Chu Ya, bless her heart, accepts Qilan's invitation for a meal at the eldest son's residence. At dinner, Jiangli sends over some pastries. Chu Ya, never one to mince words, openly confesses her crush on Lu Jingming from way back when he rescued her five years ago. Jiangli, trying to be diplomatic, reminds Chu Ya that she and Jingming are tight and have a kid on the way. But Chu Ya's not having it! She defiantly chows down on a pastry and BAM! Stomach cramps from hell.
Jiangli immediately calls for the doctor and tests all the food. No poison! Super sus. Jiangli grills the maids about everything Chu Ya ate that day and learns about the snacks at Jingxiu's place. Then it clicks! The mandarin fish she ate earlier, combined with the Fuling (茯苓) cakes at dinner (甘草茯苓糕点), created a toxic reaction. Jiangli whips up an antidote, saving Chu Ya's life.
But a Xizhou princess getting poisoned on their turf is a HUGE deal. Jingming and Jiangli interrogate their maids, and one cracks, admitting that Shen Qilan paid her to stir up trouble because her brother has gambling debts. She spills the beans about the phosphorus on the lanterns and the poisoning plot. Jingming tells his father everything, and Grandpa Lu is furious! He throws Qilan in jail.
Qilan, who thought she was helping her husband by taking down Jiangli, is abandoned by Jingxiu. He can't risk angering the Dongzhou governor. However, he slips her a key to the prison, hinting she should punish Tingyuxuan.
Qilan escapes, torches Tingyuxuan, but Jingming catches her. Jiangli is heartbroken to see her sister-in-law hit rock bottom. Qilan, in a moment of clarity, laments her life as an unloved illegitimate child, always scheming but never succeeding. She calls Jiangli "sister" one last time and takes her own life.
After Qilan's burial, Jiangli is devastated. Jingming comforts her, saying Qilan's actions led her to this end.
Meanwhile, Jingming, who's been investigating an inside man in Dongzhou, learns that the spy he's been watching has infiltrated Lu Jingxiu's residence. Jingming heads off to investigate!