Overdo

Overdo has a sad ending, as far as we can tell from the episode summaries. Murong Qingyi does not survive the final battle. Ren Susu lives and leaves with their son. There is also a short "what if" sequence in which the main couples get a happy life, but the story itself ends in loss.

This account comes from Chinese episode summaries for episodes 22 to 33, not from watching, and the summaries disagree on a few details.

The wedding. In episode 22, Murong Qingyu's wedding goes ahead, but the bride is Ye Zhihong, not Susu. Susu aims a rifle at Li Rongzhang from an upstairs window, but her shot goes wide. Huo Minxian bursts in and shoots at the bride, and Qingyu is killed shielding Ye Zhihong. Zhang Mingshu shoots Huo Minxian dead. After the wedding, Qingyi exposes his mother Cheng Jinzhi's part in the old Murong family tragedy and cuts ties with the family. Susu tells him she no longer loves him to push him away. He burns the cottage they shared, and she learns she is pregnant. Li Bozhe offers to protect her and the child, and Qingyi leads the flight school's squadron to the front.

Years later. The story skips ahead by several years. Their son, Le'an, is a toddler, and Qingyi has been nicknamed the "Blade of the Sky" at the front. When he and Susu meet again, she is married to Li Bozhe and Le'an is presented as Li Bozhe's child. Qingyi notices the boy's allergy to broad beans, suspects he is the father, and in episode 27 asks Susu to marry him in public and tells Le'an the truth. In the same stretch a mysterious train carrying "red pills" (红丸) points to the Zhang family, backed by a Japan-linked chamber-of-commerce chairman, who have been using Li Rongzhang as cover. Zhang Mingshu has Li Rongzhang framed and jailed. He escapes and blows up the train and the pills at the station in episode 29, dying in the blast.

The epidemic. In episode 30 the city is sealed off when the red pill is found in the flight school's water tank. Qingyi falls ill and Susu nurses him. In episode 31 his childhood memory returns: he was drugged and thrown into a river and pulled out by the Ren family, who were later wiped out by a fire. That is the 19-year-old secret Susu had kept from him. She says she loves him. When Li Bozhe appears to shoot Qingyi and burns Haitang Qing with a coal, it is a staged plan worked out with Qingyi.

Losses. In episode 32 Li Bozhe infiltrates the Zhang camp and stabs the chairman with a poisoned pen. The attack costs the enemy side almost its whole force, and Li Bozhe dies in it. Haitang Qing receives his letter, which says the burn was meant to protect her, and retreats to the suburbs to live with opera. Ye Zhihong bombs the rail line and crashes her plane into the secret drug factory, dying with it.

The finale. In episode 33 Qingyi and Susu bury Li Bozhe and Ye Zhihong and agree that they will lie together one day. Zhang Mingshu plans to poison the temple-fair water supply with an improved red pill. The couple split up to stop him. One of Qingyi's men dies shielding him. At the waterworks Qingyi and Zhang Mingshu fall in an explosion, and Qingyi is trapped in the fire and doesn't come out. Susu receives a last letter or keepsake from him (the summaries differ) and takes Le'an south. After the main story, the drama shows a parallel world in which all three couples marry and have children.

We couldn't confirm Zhang Mingshu's fate (one summary says the poison kills him, two others don't say) or what happens to Cheng Jinzhi. A blog post reported that Susu stays behind after Li Bozhe's death, which we haven't seen elsewhere.