One possibility is that Boris Johnson manages to negotiate a new agreement with the EU. But time is scarce and from the EU's side it is stated that the British have so far not been able to present any concrete proposals to dissolve the knots, especially regarding how to manage the border with Ireland.
On the other hand, others point out that the EU would like to have a hard Brexit because it would hit the economy and trade - and that it is therefore likely that they will meet the British if they consider it possible, which is why yet becomes a settlement.
But if Boris Johnson and the EU fail to modify Theresa May's exit agreement and, in addition, get the British Parliament's approval for such a modified agreement, there are several other ways Brexit drama can take. See the video above for a more detailed explanation of these.
See the options in the clip