The Book of Eternity. The great wizard Merlin wrote it over 1,500 years ago. It gives whoever holds it the power to know, and thereby control, the future. The Ancients buried it under Stonehenge to keep it out of the hands of mortals. Nobody should have that book!
Lex Luthor discovers the Book of Prophecies, where he can create any future he wants. Zee worries that Lex will use it for evil, so the girls are about to break in LexCorp to retrieve the book, until Babs was forced to go with her dad. Now, the rest of the girls reluctantly need help from Catwoman to sneak in LexCorp, though it was not as easy as she predicted. As they go inside his secret base, Lex reveals himself as a criminal mastermind and shows the girls the captured Invinci-Bros, including Superman, who is incarcerated with Kryptonite. As if it was not bad enough, Catwoman unironically betrays the girls and joins Lex. With the Book of Infinity in his hand, Lex effortlessly defeats the girls and locked them up inside. As they were about to head out, Lex tells Catwoman that what he wrote in the book is to predict a meteor that will destroy Metropolis so he can enslave the survivors and rule not just what's left of Metropolis, but the entire planet. Catwoman is shocked about Lex's evil plan, so she sneaks back into LexCorp and frees the girls to stop Lex. Supergirl destroys the meteor that Lex predicted, while at the same time, Catwoman ripped out a page from the book and steals it from Lex, though the girls retrieve both from Catwoman. While Babs was disappointed that they saved the world without her, the rest of the girls are disappointed that Lex wasn't revealed as a criminal mastermind and that he remains a good guy to the world. Meanwhile, Catwoman sneakily steals all of Lex's gadgets and food from him, with the Bros and Superman still locked inside.