It's a comparatively lightweight but thoughtful manga about gender-bending. It's short. I wish it were longer.
Nozomu is an ordinary boy on his school's baseball team. "I wish I were a girl..." Okay, apart from that. One day his team loses a game and their coach makes them dress up as cheerleaders.
"It was a bet, guys. We've got to make good on it. You guys aren't cold dressed like that, are you? Well, it's good you guys already finished changing; we've got to hurry to the station."
Most of the boys look ridiculous, but Nozomu in drag looks so convincing that he's mistaken for a real girl. He pretends to be insulted, but... "the truth is that I was very pleased when I was mistaken for a girl. So what should I do, father? I might have found something I like doing more than baseball."
The title, by the way, comprises Nozomu (boy's name) and Nozomi (girl's name). It's also a word meaning "wish, desire, hope". At first he's just exploring his new taste for cross-dressing. He's wearing his little sister's clothes. However one day he feels down there and discovers unfamiliar genitals. Nozomu is now physically "she".
This isn't a deep, angsty manga. It's fun. It has short chapters (in full colour throughout!) and the premise is magical, not realistic. Nozomu even finds a charming ally in his sister Kaede, who's so supportive about her brother's penchant for girls' clothes that she'll even take him clothes shopping. If Kaede comes in while Nozomu's changing, the comedy doesn't come from being seen in her panties (which she expects) but instead from him trying to hide how well they fit. The manga also has a fair amount of sexual content, including masturbation (both genders, solo and assisted), explicit dreams and incorrigible teenage boys.
Nonetheless it's also a rather well-written exploration of gender roles, sexual identity and Nozomu's self-image. In ch.2, he thinks what he's doing is weird. In ch.3, he's telling off his sister for violating gender stereotypes even after having his junk go for a walk. In ch.5, he's telling Kanae what kind of panties he'd prefer and wondering if he'd be attracted to a particularly cool boy "if I were a girl". In ch.6, he's crying and hanging out with Kanae's friends. Sexual questions soon come up and Nozomu's mind gets put through the blender. (Baseball training camp with all the other boys on the team is no place for a girl, especially when no one's realised his secret and so everyone's sleeping side by side. Disturbingly, it seems that whacking off to porn videos is a communal activity.)
Slowly, subtly, Nozomu's self-image drifts from "he" to "she". It's complicated and he'll try to preserve little islands of masculinity within himself even after discovering that he thinks of boys when masturbating. Weeks go past, then months. Summer becomes winter, then it's Valentine's Day. He starts growing breasts. He starts having periods (which baffle him until he works out what they are).
All this gets explored. It's very well done. We see Nozomu's thought processes, which feel as if they must be close to lots of people's real experiences while obviously also being unique. He resists the idea that he's changing, then later finds more nuanced things to be afraid of. "I'm scared I'll forget everything from when I was a guy." Essentially this is a 250-page story of Nozomu's journey to self-acceptance.
Then there's Kanae, who's Nozomu's mirror in many ways. She lets the story exploring similar themes, but from the other direction.
I like it a lot. I think the sexual material earns its place, being a legitimate and crucial part of the story instead of just being another ecchi manga. Nozomu's sexuality is... complicated. There's a hand job near the end that I think is strongly implied to be a blow job, but the circumstances are (very very) unusual and even after that Nozomu's still managing to say things like, "But that is a line I've refused to cross. It's where I've drawn my last line of defence as a man." I could imagine transgender people possibly being offended by this story, since you could choose to read it as implying that body defines gender, but I also think it's so deftly and sensitively written (despite the adult content) that I'm sure most people would be won over. Besides, it's not pretending to portray a real situation. It's magical.
Just don't read it on the train to work.