Smile Baby ~Baby Panic~

Smile Baby ~Baby Panic~ is the fifty-first chapter of the To Love-Ru Darkness manga series.

Summary
On her way home from school, Yui sees a couple going for a walk with their baby, whom she smiles at, causing her to imagine what it would be like if she and Rito were to have children.

Meanwhile, Rito finishes up helping his father at work, and begins to head home. He is stopped by Nemesis, and is surprised she's still in the city. She begins playfully flirting with him, telling him that now Mea has parted ways with her, he's her "one and only beloved servant". She begins to pull him closer to him seductively, until suddenly spraying him with a mysterious gas. She reveals that the gas is 'gigantification gas', which she acquired from a smuggling organization she had destroyed for fun the other day. She explains the gas was used as a biological weapon during the Galactic War, turning anyone who came into contact with it into a giant until it was dealt with by the forces of Deviluke. Wanting to see its effects on Rito, she activates the power of the gas, ordering him to show her the legendary powers of giants.

However, after the transformation, Rito is turned into a mere baby, laying naked in his now over-sized school clothes. Nemesis makes conclusion that the gas has an age-reducing effect on humans. Not wanting to leave him alone as such but also not wanting to be stuck with babysitting him, she notices Yui walking by and gets an idea.

Yui looks at her phone, and finds out her parents are out at a drinking party and Yuu is out with friends, and thus will be by herself for the rest of the day. Nemesis then comes up to her, in disguise, and hands a confused baby Rito (now dressed in a pair of footsie pajamas), over to her, asking her to "help someone in need". Yui asks if they've met before, but Nemesis tells her not to worry and to do her best with him before she runs off.

Yui holds Rito to her face and stares at him, thinking that he looks familiar. Her serious expression causes him to start crying, attracting the attention of Matome. He asks her what she's doing with a baby, and asks her if he's hers despite her not being out of high school yet. Everyone nearby overhears this, looks at Yui, and begins judging her for (apparently) being an underage mother, humiliating her and forcing her to run off with Rito sobbing in her arms. She then comes across Mikan, who asks her why she's holding a baby, and begs her to help stop his crying.

At the market, Momo is thinking to herself about her mother now knows about the harem plan, and what it could mean for her personal relationship with Rito. Nemesis shows up, no longer in disguise, and greets Momo, who angrily asks her what she's doing here. Nemesis responds by tossing her Rito's school bag filled with his old clothes. Momo assumes it means Nemesis has placed Rito in sadomasochistic danger, and runs off to find and help him. Nemesis notes how defensive of Rito Momo is, and walks off to eat some more dango.

At the Yuuki household, Mikan is cradling the now happy Rito in her arms, deeming him "cute" while Yui mopes in the corner. They discuss how 'some stranger' just dropped him off on them, and how they'll be able to get him home, not realizing who he really is. Mikan points out that, since the person knew Yui's name, she'll most likely be back in a while to pick him up. Yui agrees, and compliments Mikan on how good she is with handling the baby. Mikan responds by saying she and the baby seem to be "on the same wavelength", and how much better Rito would be with him, since he took care of her when she was a baby and since he's had great experience with raising Celine.

Rito then lifts Mikan's skirt up and begins crawling around inside. Yui tugs him out, lifting him up and firmly stating she wants a turn playing with the baby, much to Mikan's shock towards her abrasiveness. Rito begins crying again, while Yui tries to tell him to play with "Onee-Chan". Rito, having been taken away from who he wanted to play with, only cries harder at this. She then lifts him into the air in an attempt to 'play' with him, but only succeeds at upsetting him even further. Rito then pees on her, soaking her and leaving her miserable as Mikan changes him out of his wet clothes. Yui notes he wasn't wearing a diaper, so Mikan decides to go out and buy some while the two of them wash themselves off. After taking his footsie pajamas off, Mikan looks him over and determines "it's a boy". This causes her to reflect on when Rito used to help change her, making her embarrassed as she leaves to get the diapers.

In the shower, Rito happily plays with a soap dispenser, pressing down on the nozzle and cooing. Yui becomes annoyed when the soap keeps hitting her, and responds by forcibly taking the object away from him. Rito breaks into tears yet again, Yui panics, and she tries to calm him down by telling him "the water's warm". Rito dries his eyes and notices her bare breasts, and smiles as he reaches out to touch one. He grabs one of her nipples, making it harden, and begins to suck on it due to his new infant tendencies despite Yui telling him she "doesn't have anything coming out yet". Rito continues 'nursing', while Yui is overcome with a strange feeling. After a moment, she lowers her defenses, cradles him in her arms as she lets him enjoy the experience, and identifies her feeling as happiness while she knocks the soap dispenser away.

A while later, Rito is clothed and happily hugging Yui's leg and playing with her left breast, while Mikan watches in amazement at their new bond. She asks if the skin-on-skin relationship is really as important as it's made out to be, and Yui embarrassingly admits to it. Momo then comes in, asking if Rito's okay, while Mikan and Yui have no idea what she's talking about. Just then, the gas wears off and Rito is turned back to normal with his old brain (not knowing anything that occurred after the transformation) and his old body (now stark naked). Mikan and Yui stare directly at Rito’s penis, trying to process what just happened, and Rito asks what just happened and where he is. He notices his nudity, and asks where his clothes went, while Mikan simply remains annoyed towards the situation and a horrified Yui calls him "shameless" before slapping him.

Later on, Nana, Lala, and Celine come back with Gigainoshishi (Giga Boar) babies that were just born in the Cyber Safari, where they had just helped the mother give birth. Nana asks why Rito's cheek is swollen, and he responds by confusedly and indifferently saying "stuff happened" while Momo sympathizes with him in her thoughts.

Meanwhile, Nemesis sits on a rooftop eating dango and hanging out with cats, declaring that Sainan is the perfect town for her to have fun in. Yui grumpily lays under her bed covers at home, mortified, as one of her family members tries to call her down for dinner.