It's possible to trace Pearl's and May's journey from Shanghai because the Shanghai offensive in the second Sino-Japanese War, part of World War II, began on August 13, 1937. The day after this, on August 14th, Pearl and May go out shopping for next year's fashion trends to keep abreast of the requirements of their calendar modeling jobs. They see the swarms of people yet have no understanding, then are themselves in a collection of victims who suffer from a direct hit of an aerial bomb on Shanghai. Tommy is killed, and May is buried under rubble until Pearl finds her.
We are told that they leave on the August 15, 1937, for their journey to the Grand Canal, which takes three days. We know that their ferry journey to Hangchow takes two days. We know they stay at the hospital in Hangchow until early October since Pearl was confined six weeks after her surgery. We know the fisherman's boat arrives in Hong Kong a few days later after her discharge. We know that when they see Pockmarked Huang, they panic and trade their old tickets, which they still hang onto, for two tickets to San Francisco, a journey that takes about 31 days. And we know that Pearl and May arrive in San Francisco and at Angel Island on November 15, 1937:
The next morning, November 15th, we get up early and put on our best Western-style dresses. "We're guests in this country," I say. "We should look like we belong."
... When our turn comes, we hold out our papers. The inspector looks them over, frowns, and motions to a crew member.
"These two meed to go to the Angel Island Immigration Station," he says. ... Cold wind blows rain into our faces and soaks our clothes.
Once confined at Angel Island, the interrogations take days, with interims of even weeks in between interrogation sessions. We know that enough time goes by on Angel Island for May to come to full term with her pregnancy, which was only days or weeks along when they escaped Shanghai. After Joy is born, they are not called immediately in for an interrogation. When Pearl and May are called for their final interrogation, Pearl carries Joy and both she and May, in flawless English, in separate rooms, give perfect and correct answers to all the interrogators' questions.
Angel island is part of the United States, yet no one's citizenship or status is acknowledged until that person leaves the island. It's easier for the officials to release us than for them to deal with the bureaucratic problems Joy presents.
It is at this point that in frustration the chief interrogator, Chairman Plumb, tells us in vexation just how long Pearl and May have prolonged their stay at Angel island--one might say in the protection of the angel's until Joy is born--in order for May to be safely delivered of her child without advertising to the Louies that she was unfaithful to her child groom. Pearl and May were at Angel Island for "more than four months." If they arrived on November 15, 1937, four months would take them to mid-February, 1938. More than four months then would reasonably be anywhere between the end of February and the first few days of April.
Chairman Plumb ... [is] hardly happy when he comes to his concluding words: "The submission of this case has been delayed for over four months. ... [This woman] has now given birth at our station. ... I therefore move that Louie Chin-shee be admitted to the United States as the wife of an American citizen."