UNMARKED SPOILERS
- Milan's repeated attempts to bring back Sinbell is enough of a tearjerker, but then the last few chapters reveals she's actually Sinbell's former biological mother, Aya, after performing a Heroic Sacrifice to save her son, and for her last words being to have her consciousness reprogrammed into a robotic body so that she can continue being Sinbell's mother.
- The first half of the story have Sinbell being a massive jerkass to Milan in almost every scene, telling her to "Back off! Get away!" whenever Milan tries caring for him, due to the Fantastic Racism between humans and robots. And Milan swallows it all in stride, for she's a mother who loves Sinbell even if Sinbell doesn't love her back.
- In another flashback, one of the junior classmates in Sinbell's school lost his parents, and was issued a second-grade robot mother who spanks him from crying after missing his real mom. Said classmate later leaves school without a trace after becoming an outcast among his peers and facing constant bullying from everyone in school. With Sinbell being the only person who shows any signs of empathy, because Sinbell's mother is a robot too.
- Milan is so proud over the fact that her son, Sinbell, got the highest grades in class, and is all kinds of excited to attend a parent-teacher meeting (even picking a floral dress for the event) only for Sinbell to tell her the event's been cancelled. Milan, while initially dejected and upset, later swallows her pride."It's okay. This dress is too colorful anyway. It doesn't suit mommy... It's just mommy always imagining herself going to the meetings, and all the other parents will be jealous of mommy. Mommy is not trying to show off, but mommy just feels really proud of your achievement. You'd understand, right?"
- After Sinbell's first attempt at running away from home due to being ridiculed by his classmates for having a "robot mother", a worried Milan and the neighbor, Aunt Slado, tries looking for him. They found him alright, unconscious in some tall grass, and when Milan tries carrying Sinbell back home, Sinbell's response upon waking up is to push Milan aside and scold her for waking him from a nap. Not cool.
- In one of the manhua's more emotional moments after Sinbell ran away from home for several days, Milan eventually finds him and gives him a tight slap, in an Anger Born of Worry moment... only to suddenly break down and apologize to Sinbell for hurting him. Despite Sinbell deserving that slap for being an ungrateful dickwad. Sinbell's response doesn't make things better:Don't touch me! I hate robots! I hate you mother!
- Sinbell finally losing it and reveals why he tries distancing himself from Milan:"I just want to live a normal life like other kids! Kids with a real mother! Real flesh and blood... and alive! Do you know why I don't want mom to show up at school? Because I don't want people to find out I have a robot for a mom!"
- When Sinbell seems to have found his "real mother", Asara the prostitute (actually an Identical Stranger), he then sends Milan off in the rain. For a while he wonders if his robot mother is feeling sad over the farewell, but then assumes Milan couldn't feel anything because "she'a a robot, with no emotions". You can see the sadness in Milan's mechanical eyes, from being rejected and disowned by her son.
- Sinbell eventually have a Jerkass Realization and returns to Marloq, only to find the whole village deserted of robots. And finds out all the robots - including Milan, his mother which he spends the whole story rejecting - is to be recalled and destroyed.
- The Undying Loyalty Milan displays by being Sinbell's Mysterious Protector, for two years after Sinbell sends her back to Marloq.
- Sinbell eventually discovers the truth, when Asara reveals she's NOT his biological mother - she's playing along because Milan paid her to do so.
- Milan's second Heroic Sacrifice as a robot, in the destruction of Cantal, while shielding Sinbell - now reformed and remorseful over his actions - from a nuclear strike. And Sinbell having a Regained Memories Sequence of his past, how his biological mother Aya shielded him from a gas explosion when he was four.
- The last we saw of Milan - a Single Tear from Sinbell, dropping on her remains.
- There's a dedication in the last page (before the flashback chapter), from the author Wang Xiao-yang himself, who wrote the entire story as dedication to his mother:Dedicated to all the mothers in the world that has worked hard and sacrificed for the happiness of their children.
