And so, Newt and Jacob set off for the Ministry of Magic. Rather than use Floo powder to go directly to Tina's office, they walked down the streets of London, talking about their top-secret mission in full view of various onlookers and potential eavesdroppers. However, the streets of London looked really moody and atmospheric, so I think we can all agree they made the right decision here.
"I don't understand," said Jacob, after Newt had explained the situation. "How could this one toenail destroy all the fantastic beasts?"
Newt sighed. "Well, it's a long backstory. Would you like it explained in a lengthy, overly dramatic way that's still very confusing?"
"Okay!" Jacob agreed cheerfully.
With that, Newt went on to explain the history of Jupiter Icklibõgg, a Dark Wizard who came to hate all fantastic beasts as a result of stepping on a Doxy one time. Newt didn't even get around to that part for quite a while, instead covering Icklibõgg's entire family tree, dating back to his great-great-grandfather, Silas Icklibõgg. Newt made sure to load this story up with plenty of extraneous details, focusing particularly on the time the various family members spent at Hogwarts because we're all nostalgic for adventures at Hogwarts. At the same time, he left huge gaping holes in the narrative that made it impossible to follow. And at the end of all that, he didn't even explain how Icklibõgg's toenail was imbued with such awesome powers, which you'd think would have been the whole point of the story.
Needless to say, Jacob was more confused than ever after hearing this "explanation," but didn't want to say so because he was afraid it would make him look stupid. Besides, Newt was giving him what he asked for, more or less, and he didn't want to appear ungrateful. Thus, Jacob just kept nodding along as though he understood what Newt was jabbering on about. By the way, it turns out Jacob has autism. This is canon now.
Anyway, they had arrived at the Ministry by this point.