How does scene one conclude?

After Horatio has finished explaining this political backstory, the ghost of Old Hamlet appears once more. This time Horatio does try to speak to the ghost. When the ghost remains silent, Horatio tells Marcellus and Bernardo to try to detain it; they strike at the ghost with their spears but jab only air. A rooster crows just as the ghost appears ready to reply to Horatio at last. This sound startles the ghost away. Horatio decides to tell Prince Hamlet, Old Hamlet’s son, about the apparition, and the others agree.