In our first installment of Twice-Told-Tales, which highlight either the parallel nature of the Multiverse or the lack of creativity leading to the rehashing of old tales, we find Barry "the Flash" Allen in two quandaries with similar elements in each. He wakes up to worlds not his own, on Earth-One in a hospital bed in Central City General and Earth-Two on a plot of land outside Keystone City.
Then things turn curiouser and curiouser for the scarlet speedster in these separate tales in Flash Comics #300 and Adventure Comics #460. The latter tale began with a race between Barry and counterpart Jay, at which point he attempted to return to his own Earth.
He learns that his "wife" is now married to another man and each has a son (and Vicky Grant, apparently, in Iris' case). While his real wife Iris states she couldn't keep waiting for the comatose Barry and fell in love with Wiley, his counterpart Jay Garrick's wife married arch-enemy the Fiddler. Looks that's Fiddler Jr plucking away on the floor!
Soon he comes to the realization that everyone believes he is something other than he believes himself to be, either plain Barry in bandages or jealous Jay. When he encounters Professor Zoom who is somehow a Reverse Flash (who liberates him from his bondage out of his good nature and the suggestion of Barry's benevolent doctor, he likewise encounters Mayor Shade of Keystone who absolves him of charges despite assaulting the rogue turned elected official (aren't all elected officials rogues?) after a brief duel between the two. Oddly enough, on Earth-Two they all see Barry appearing as Jay, such as Zoom is a Reverse Flash with the original being exactly who? As the mystery thickens, Flash becomes increasingly suspicious in each case and is determine to find out what's exactly going on.
While in the hospital bed on Earth-One he traces his history and that of his friends and foes from the beginning to the present to restore his sanity, its hard for him to get his bearing on Earth-Two... and Earth that is not his own and which he's only visiting a handful of times personally beside reading about it in comic books as a youth.
While he is able to ascertain Abra Kadabra was behind his bedside dilemma whereby all present, including close friends Green Lantern and Elongated Man, and Iris herself tried to dissuade Barry from his Flash "illusion"... each of them being illusions; on Earth-Two his attempt to return to his home world revealed the hand of the Wizard. No doubt picking up on the theme in Secret Society of Super-Villain's issues wherein the arch-criminal was directing his team towards taking out individual members of the Justice Society during this period, evidently he realized that Flash was the hardest to catch and left that hero for himself to defeat in a dreamlike illusion between both dimensions. However, he caught the wrong Flash in the process. In each case, the Flash wakes up and regains his bearings in the world. And would go on to defeat each criminal shortly thereafter.
But there is still another Twice-Told-Tale for us to consider highlighting the parallel lives of this pair of felons.