It has been one of the hottest weeks of the summer. In such hot weather, there was a greater danger that ships might be carrying diseases. If this was the case, the ships would have to go into quarantine for several days and wait out in the estuary, away from the harbour. Under no circumstances should any of the tugs go near the ships in quarantine. Ships in quarantine fly the yellow flag. When the old tramper, Nantucket, lowers its flag, a great deal of confusion is caused and only wise old O.J. understands why.