: Iris pursues the secret organization "Black Hole," which has been using metahumans as assassins. This storyline grounds the season’s second half in a more grounded, noir-inspired mystery.
“"Marathon" deals with the fallout of Crisis while setting up the second half of the season... it manages to be more gripping and heartfelt than that boring, anticlimactic waste of a crossover was.” Geeks + Gamers · 6 years ago [S6E10] Marathon
"Marathon" effectively transitions Iris West-Allen from a supporting love interest back to her roots as a fearless investigative journalist. : Iris pursues the secret organization "Black Hole,"
: Barry receives a parting gift from Oliver Queen—Oliver’s original mask—which he obsessively treats as a clue to a final mission. His struggle to let go of the "hero's burden" reflects the episode's central theme: the difficulty of slowing down. it manages to be more gripping and heartfelt