Collaborating with ATF to arrest an illegal arms deal, Five-O leans on imprisoned career criminal JC Dekker to learn the coordinates. Instead, they underground parking collapses as a bomb explodes. Steve is trapped with Danny, whose pessimism peeks as he's wounded under rubble, which is hard and dangerous to clear, so Steve ends up blasting them an improvised way out while inspiring Danny to a more positive attitude instead of seeing disasters everywhere, like his daughter Grace catching him after sex with Amber Vitale. Meanwhile the corpse he found under the rubble is identified as JC's clean kid brother, so Five-O examines possible theories of a trap set for them and/or JC, whose cellmate 'Spider' was paid to get the false tip.
—KGF Vissers