
At first glance all is not what it seems. Guinan's El Aurian intution senses whats wrong. The weird thing is the Enterprise-D isn't supposed to be a ship of WAR but of PEACE! She fills in the gaps for Picard who has a tough time buying her story, especially the bit about FAMLIES living on the Enterprise, LOL.

Captain Garret's ship has to go back to 2344 and save Klingons in THE PAST because its the right thing to do. Its a suicide mission dooming the Enterprise-C to certain death but the Picard is desperate and Guinan is probably right.
One more Federation starship in the here and now hardly matters, but 22 years ago, a lone Federation starship rescuing Klingons at Narendra III would be considered 'a meaningful act of honor' by the Klingon Empire.
In the end Tasha Yar, Castillo and the Enterprise-C crew heroically race to their deaths giving Picard's alternate universe a fighting chance to survive but what would you do? Stay on Picard's ship or die heroically fighting Romulans?