Again! is a time-travel story concerning two characters - the first is a lonely guy for whom High School was pure misery. Ostracised and friendless, Kinichiro has no fond memories to accompany his graduation and little to look forward to in life. By contrast, Aki is a bright, popular girl who has a great boyfriend and much to look forward to. After a chance encounter after the closing ceremony, the two are involved in an accident that should kill them - instead, they are sent back in time 3 years to do it all... again!
Mitsurou Kubo's terrific tale (kinda spoiling the score here) is a real page-turner. Kinichiro embraces the chance to wilfully alter early events of high school to try to make a better future, while Aki is having the opposite problem - eager to step back into her role as she left it, she scares off her future beau and alienates her previous friends! By remembering how it all happened before, these early changes set them on very different paths, and it's a real treat to see how things turn out.
What's even better is that they both understand what's happened pretty fast, and recognise each other early on. So you have a dynamic wherein both protagonists can confide in each other (or in Aki's case, someone to blame and slap about) and explore the ramifications of every change that's being made. Kinichiro's dour-yet-hopeful demeanor makes him very endearing, while Aki's slide into desperation makes for an entertaining, albeit sympathetic, co-lead.
Aiding the story is some excellent artwork - a more mature style than I would expect for this sort of tale, you can absolutely see why someone with Kinichiro's bleached hair and glowering eyes would be left to his own devices (shades of Toradora here), and some of Aki's expressions are absolutely priceless. There's lots of detail and the sense of urgency is illustrated superbly where required.
The use of an Ouenden (cheering) club is also rather fun. I have fond memories of watching friends play the game of the same name on the Nintendo DS (I sucked at it) and sets up a solid rivalry with the cheer-leading club. With Kinichiro unused to such rivalry, it's fun to see his bewilderment at the politics deployed.
Is Again! particularly original? I guess not, it's a hodge-podge of other influences, but honestly what isn't these days? What is here is presented in fine form, from the art to the writing, it may be the sum of multiple stolen parts, but the end result is really rather splendid. If you ever wished you could relive your high-school years, this is a fun bit of wish-fulfilment fantasy.