Urban Leap tells about a kangaroo, Garoo, who was accidentally delivered to a young couple's apartment in the mail. Despite Garoo's self-sufficient nature and hard exterior, he ultimately proves to be a decent family member. Adapting to city culture after living in an outback full of dingos is hard on him, but before long the reader has no choice but to fall in love with this cheeky Australian wallaby!

Hedwig Brinkerhoff and Kosmo Hilliker are domestic partners - or at least they live together, forming a family unit, the dynamics of which are tested when the daredevil Garoo arrives, greatly complicating or scuttling many of the couple’s plans. Kosmo is an IT geek who often works from home, the economic head of the household, but Hedwig, who is just finishing school, often seems to be the one who wears the pants around the house. Sometimes Kosmo even ends up lower in the pecking order than his rude Aussie pet.

The living room of the home is watched over by Diona, a carnivorous plant, who in addition to capturing of flies tries desperately to snag every man who comes along. Garoo sometimes ends up in the line of fire too, but usually manages to slip away unscathed.

Just to stir the pot even more, an alien from beyond the stars is subletting in the family's bathroom: Noid is actually of the humanoid elite and a more refined alien would be hard to find this side of Aquarius, although due to his technical superiority this sexless creature looks on humanity like laboratory rats and so comes off a bit snooty.