(Exact circumstances may have varied for different characters; this is a generic introduction.)
On the evening of evening of August 26, 1925, you were contacted by a messenger at your residence in San Juan, informing you that your ship, the USLHT Maga, was to sail for Navassa tomorrow, a week ahead of expectations.
While the Maga hastily prepared to get underway, the tender's master, Captain Jacobson, explained that an Eastbound ship had seen the flag of the United States flying upside-down from the light station on Navassa Island that morning, and informed a shore station by radiotelegraph. Word had reached the headquarters of the Ninth Lighthouse District in San Juan that afternoon, and it was decided that the Maga, already stocked with most of the cargo to resupply the Navassa light station, should be sent to investigate.
The weather during the later half of your journey from San Juan to Navassa was stormy, but the sea was calm by the morning of the 29th. No more news of the island reached the Maga by radio before the island was sighted in the early afternoon.
Through a telescope, Jacobson managed to confirm the reported distress signal. With the Maga anchored off Navassa, the captain decides to send you to investigate onshore using one of the boats of the Maga...