Big and Small are machines that work together as a team building and filling trenches. However, some days Big gets a bit wobbly. He imagines he is a boat and starts to sink, for example. He malfunctions and Small tries to help but Small is confused and scared. Small wants his friend to be well. The Boss and Mechanic also try to help. First, they get him tractor medicine to help Big’s computer, and that works for a time, before he goes “wobbly” again and needs to go to the workshop.
The story is a metaphor for a child living with an adult who suffers from mental illness. Small gets scared at one point in the story when Big starts throwing things at him. It touches on the very real experiences that many young children encounter dealing with mentally ill parents. In the story’s resolution, Big Small learns that Big will always have problems with his computer, but if he continues his medicine things will be fine. The story concludes with a realistic hope for a child living with an adult with mental illness. Small also shares his experiences with a friend Tich, who has a similar problem with a machine called Titan. It is a gentle suggestion that sharing issues with a friend can help. The story also highlights the need for others to support those dealing with mental health issues. Small relies heavily on the Boss and Mechanic to help fix Big as he knows he cannot do that on his/her own and the Boss and Mechanic are there to help.
The illustrations are dramatic. Miller uses paper sculpture effectively to make the characters appear to be 3D. The machines appear almost comical with their google eyes that humanise them. The backgrounds are a simple wash that makes an effective backdrop for the writing and supports the setting of a construction site.
The font used for the narrative is clear, emphasising key words and phrases in larger bold font. The choice of words is simple and would have a low reading age. The amount of text on each page is not usually more than 4-5 sentences and arranged on the page to complement the illustrations. The choice of names of the two main characters – Big and Small clearly is to make it as simple for younger readers as possible and Small has no gender, making it easier for any child to identify with them.