The plot might involve Alice and the Hatter falling deeply in love first. Then, due to some unforeseen magic, Alice discovers she is pregnant. The Hatter, being his eccentric self, is initially overjoyed but then realizes the huge responsibility. They could go on a journey to find a way to ensure the safety of Alice and the unborn child in the often unpredictable Wonderland, with many adventures along the way.
Well, one possible plot could be that Alice and the Hatter accidentally find themselves in a situation where they are expecting a child. Maybe they were caught up in some magical mishap that made it possible. They then have to navigate the strange Wonderland while dealing with the upcoming arrival, facing the reactions of the other Wonderland characters, some being excited and others being skeptical or even trying to interfere.