Supergirl (2015)

S1E18 Worlds Finest

Title: Worlds Finest Plot: Kara welcomes an unexpected ally to her side when The Flash, a super-speed hero from another universe, arrives to assist her. Together, they confront the formidable duo of Siobhan, known as Silver Banshee, and Livewire. In return for her support in defeating these villains, The Flash seeks Kara's aid in discovering a way back to his own world. Their partnership proves essential as they face off against powerful foes and navigate the challenges of interdimensional friendship.