Taichi's very romantic plan for not only Hayato's birthday but also Valentine's day, which perhaps coincide. This summary is awfully unbiased, so incredibly unbiased that you should be surprised to find it's from Taichi's point of view and his plan is, perhaps, not quite so romantic as he makes out. But it's for Hayato, and so characteristically scuffed for the both of them. Isn't that all that really matters? AKA a married kawagata get up to birthday + Valentine's shenanigans in their own haphazard manner