Toradora! is just your typical romantic comedy. You know, boy meets girl, girl punches boy, girl breaks into boy's apartment and tries to murder him, girl makes boy her slave and forces him to clean her apartment and prepare her meals. Classic Tracy and Hepburn stuff.
Ryuuji is a nice boy. Really he is. You'll never find somebody as kind, even-tempered and clean as Ryuuji (seriously, this guy is OCD about mold). He takes care of his mom, a hostess at a businessman's bar who spends her life alternating between being drunk and hungover with no period of sobriety between. Unfortunately he inherited his looks from his deceased yakuza father, particularly a pair of eyes that make him look like he's going to murder anyone who pisses him off. It took him most of his freshman year in high school to convince his classmates that he's not a thug, and now that he's starting his sophomore year with a new class, he's afraid he'll have to start over.
On the first day of school he discovers that Kitamura Yusaku, one of his friends from the year before, will be in his class, which is good. Even better, Kushieda Minori, the girl Ryuuji has a crush on, is there as well. So maybe this won't be such a bad year after -- hey, what's this! As he's entering the classroom, Ryuuji bumps into (literally) the only person in school more intimidating than himself: Aisaka Taiga, more commonly called "the Palmtop Tiger" for her diminutive size and fierce nature. Students immediately gather round to witness a clash of the titans, only to be disappointed when Taiga delivers a first round TKO. Well, at least everyone's less inclined to believe Ryuuji's a hardass.
A few days later, Ryuuji's doing his homework when he finds a love note from Taiga to Kitamaru in his bag. Apparently she screwed up and put it in the wrong backpack. The problem is, she realizes her mistake and breaks into his apartment that night to retrieve the letter. When Ryuuji catches her, she tries to beat him to death with a kendo sword. He fends her off and placates her by fixing her dinner. Turns out she's living on her own (in the posh high-rise apartment across the street, no less) and though her parents give her plenty of money to survive on, she has no housekeeping skills and has been subsisting off convenience store food. This is the first genuine meal she's had in weeks.
Ryuuji tries to cheer her up by showing her the box full of poems, mix tapes (well, mini-discs) and letters he's made for Minori. Finally he offers to help her get with Kitamaru -- or at least that's what he thinks he offers, though Taiga thinks he's offering to become her "dog". And Ryuuji's intimidated enough to go along with her demands, cleaning her apartment, cooking her dinner, and concocting ways for her to talk to Kitamaru. But these plans fail because, under her tough exterior, Taiga is actually a shy girl who gets nervous as hell when she's around a boy she likes. And to make matters worse, rumors start circulating that she and Ryuuji are a couple ...
I was a little trepidatious about picking this up since a ten volume rom-com epic isn't normally my thing. (Ten books might sound like a lot, but they're all what the Japanese refer to as "light novels" of only ~200 pages apiece. 2000 pages is still a lot for a romantic comedy, though it's short by light novel standards.) However, after about ten pages I was flying through the story. Ryuuji and Taiga make an hilarious odd couple, with him as the beleaguered straight-man to her insane tsundere, but with a genuinely sweet friendship that develops as Ryuuji comes to realize that beneath her hellcat exterior, Taiga is broken and lonely, and that for all her talk of him being her slave, she genuinely needs him to keep her from falling apart.
As a side note, don't expect to find this book on Amazon or in your local bookshop. From what I've read, there's no interest from American publishers in the series (most of the companies that publish Japanese fiction focus on sci-fi and fantasy). Even the anime adaptation only got a halfhearted release -- the distributor didn't even spend money on a dub track, a sure sign that they weren't expecting it to be a mass success -- so it's unlikely that an official release will happen in the foreseeable future. However, all ten books have been translated by fans, and you can easily find them by googling "Toradora epub".