When the night is clear, the inquisitive mouse Armstrong can look at the moon from her attic through a telescope: white and round and unreachable. "The moon is made of cheese!" claim the other mice and do not want to know about Armstrong's theory. So he makes a plan to prove that the moon is made of rock, just like the Earth. He will fly there and get a chunk! But how is that supposed to work? A mouse in space ... Fortunately, Armstrong gets help and thus takes on the legacy of the mouse flight pioneers. He constructs a rocket to take him to the moon and back. After weeks of experiments, experiments and failures that cost Armstrong everything - even his beloved attic and the valuable telescope - the time has finally come: the rocket takes off. According to the picture book by Torben Kuhlmann, "Armstrong" describes how a furry, four-legged inventor succeeds in the impossible. A small step for the mouse, but a big step for humanity, which is already on its heels.