Apparently when mass immigration was at its height the authorities had some concern about the potential number of undesirables who might be reaching the US -- either bomb-throwing anarchists at one extreme, or people with health conditions which might have costly implications for the welfare system at the other.

The decision was made to have screeners travel on all the ships -- Doctors testing for TB, etc, and INS agents looking for cloak-and-dagger terrorists. They interviewed the head of household (and sometimes other family members) and the interviewee was given a code letter to repeat when they were checked out after landing.

Some codes were innocuous, others meant "hold this one for questioning", and others meant "this one is infected with something nasty -- ship him back on the next boat"!

Anyway, this must have slipped David's mind, and as they approached the checking- in counters the mob of people pressing forward somehow separated him from Thana and Doris.

He was looking around, trying to get them all back together, when some bureaucrat asked him for his 'letter', i.e. the code he had been given. Thinking that the lines were perhaps set up to be 'A-J, H-K', etc, and he was possibly in the wrong line, he blurted out the initial letter of his name, i.e. 'H' ... and unfortunately that one meant 'Accept no excuses, throw him in a cell while we check him out further...'.

It took poor Thana (with sobbing little Doris in tow) several hours to sort out the mess, identify him behind the bars of his holding cell, and spring him loose ....