 This enables the boys to time-travel and participate in a short Henty-like historical adventure in which they help to relieve the 16th century Spanish siege of Leiden.This short story for boys was published anonymously in "The Sun" newspaper on September 18, 1881, and not thereafter collected or publicised.As such it was a very ephemeral and slight work for juveniles, and it was not noticed by the critics of the time.