What Caused The Fire On 'This Is Us'? The Reason It Started Was Finally Revealed & The Backstory Is Heartbreaking

Tuesday night was an emotional one for Jack fans, as answers about what started the fire on This Is Us were finally delivered. Spoilers for the Jan. 23 episode ahead. After months of speculation, it all came down to the final fateful minutes of the episode... where a crockpot, of all things, started the fire. After an episode largely built upon Randall and Kevin following in their father's footsteps by tackling some good, old-fashioned construction together, and Kate facing her fear of finally getting another dog after her father's death, the last fraction of the episode showed Jack in the kitchen, cleaning up so Rebecca didn't have to do dishes in the morning (because of course he was).

He left a note for Kevin, asking for an apology and wishing that he got home OK. He gave the dog a final pat and checked out the heights of the kids scribbled lovingly on the wall. After taking a final glance around the kitchen and shutting off the slow cooker, he turned off the lights one final time and headed upstairs to join Rebecca in bed. Except, the slow cooker didn't shut off. The light flickered back on, setting curtains and towels ablaze above the counter as a somber melodic tune played throughout a montage of flashbacks showing the Pearsons' happy times in the home. Memories were built and were now being destroyed in the very same place.

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The jaw-dropping scene was difficult to watch, and also explained away some of the red herrings that showrunners have thrown audiences in recent episodes. All those times Jack was shown messing with the breakers and the faulty fuse box apparently had nothing to do with his demise, despite the fact that all of us fans tensed up the moment he touched the wiring. The candles that were littered throughout the home as Jack worked to get the lights back on proved to be harmless, even though they easily could have toppled over while no one was looking. The smoke detector revealed last week to be without functioning batteries is the one thing we've been shown that could still have an effect on Jack's ability to get out of the home in a timely manner.

Other than that, the spark that sets off this tragic turn of events really came out of left field. The showrunners were truthful when they said that the house fire wasn't a fake out, as creator Dan Fogelman promised in a Vanity Fair interview last year. But aside from that one nugget of information, they've been keen to throw viewers off the scent of what exactly would be the cause. The slow cooker is a completely new introduction — we haven't seen Rebecca fiddle with it or Jack try and fix the messed up dial. It hasn't been something viewers have been able to stew on for weeks, which made it even more of a punch to the gut when it was finally revealed.

For all the questions that the episode answered, it also leaves so many questions. Will Randall and Kevin finally make Big Three Construction into a reality? Will Kevin finally finish up his list of those he needs to make amends to, now that he has his dear old dad's necklace back in his possession? And of course, how does this whole fire situation shake out? Why is Jack unable to get out of the house while everyone else is not only alive, but also seemingly absolutely uninjured? It seems clear that Jack is the kind of man who would ensure that his family was safe before saving himself, but what circumstances lead that to be necessary? No matter what happens, it's safe to say that the heartbreak is just beginning.