Heading into the second Democratic primary debate in Detroit later this month, former Vice President Joe Biden will have the chance to go head-to-head for a rematch against Sen. Kamala Harris (D-CA), who landed a major blow to his campaign in her first breakout performance. While Sen. Bernie Sanders (I-VT) will not have an opportunity to spar with Biden this time over health care, the Vermont senator will finally have a chance to distinguish himself from his closest friend in the Senate: Sen. Elizabeth Warren (D-MA).

The random selection was split into three parts by CNN to determine the lineups for each night, with groups based on their rankings in recent polls. On Tuesday, July 30, Sanders and Warren will be joined on stage by author Marianne Williamson, former Rep. John Delaney (D-MD), former Colorado Gov. John Hickenlooper, Rep. Tim Ryan (D-OH), Montana Gov. Steve Bullock, Sen. Amy Klobuchar (D-MN), former Rep. Beto O’Rourke (D-TX), and South Bend Mayor Pete Buttigieg. On Wednesday, July 31, Biden and Harris will join Washington Gov. Jay Inslee, Sen. Kirsten Gillibrand (D-NY), Rep. Tulsi Gabbard (D-HI), Sen. Michael Bennett (D-CO), New York City Mayor Bill de Blasio, Sen. Cory Booker (D-NJ), entrepreneur Andrew Yang, and former HUD Secretary Julian Castro.

Here are the five most interesting match-ups to watch in the Detroit debate:

The rematch: Biden will have to come prepared for a fight-or-flight rematch with Harris in order to maintain his edge in the primary. After being taken down several notches on stage in the first debate, the former vice president has since apologized and has been hitting the campaign trail in friendly territory like South Carolina, where he’s leading with African Americans by comfortable margins. But Harris will likely bring the heat in a continuation of her first pre-planned attack, which she has since said was merely pointing out significant policy differences. If Biden is unprepared to launch a successful counter-attack, he’ll risk looking like a weak candidate to go up against President Trump. But if Harris stumbles, expect Biden to go in for a pre-emptive strike against the California senator whom his campaign is eager to knock down.

Progressives crash “moderates” night: Sanders and Warren have very few tangible ideological differences. They’re both progressives. They’ve signed on to legislation together in the Senate. And they each neighbor New Hampshire, the first-in-the-nation primary state critical to the success of their respective campaigns. But they have differences in style, which is key in a debate performance. Warren leans heavily on her personal story, while Sanders is all about reigniting the core message from his previous presidential run. Sanders calls himself a Democratic socialist, while Warren is a capitalist. In this match-up, the two New England progressives will have to clearly define what distinguishes them from each other.

Look for Sanders to tout Medicare for All, the central policy position of his campaign, and to take a swipe at Warren for what some see as her ambiguity on health care. Warren hasn’t yet made significant inroads with white working-class voters–many of whom voted for Trump in 2016–to the same extent that Sanders has. But she has been rising steadily in the polls and recently out-fundraised him by roughly $1 million this quarter. She may look to capitalize on that momentum this time on stage.

The young “media sensations”: South Bend Mayor Pete Buttigieg and former Rep. Beto O’Rourke (D-TX), both young media darlings, will have the chance to ding each other directly for the first time. Buttigieg, who was coming off of controversy over a fatal police shooting in his home city during the first debate, had an exceptionally high second quarter fundraising total, while O’Rourke has recently suffered a drastic dip in fundraising and his standing in polls. Buttigieg could possibly take a few fatal blows at O’Rourke for the “rising star” lane, but look for O’Rourke to pull out a few surprises, like he did in the last debate by starting off in Spanish.

The “brain” lane: Warren and Buttigieg will be competing for the brainiac lane. Warren, a former Harvard professor who has made having a “plan” for nearly every policy central to her campaign, will get to distinguish herself from the 37-year-old Harvard alum and former Rhodes Scholar. In contrast to Warren’s plans, Buttigieg tends to speak in more generalities and is more moderate, often leaving details to be determined at a later time. While he may look to make a generational argument against Warren and the other contenders on stage, the Massachusetts senator can highlight her track record as a seasoned law professor and United States senator. Watch for them to both detail their personal stories, which have become cornerstones of their campaigns so far.

The brewing feud: Sen. Cory Booker and Biden will share the stage for the first time since the two butted heads over the former vice president’s apparently fond recollection of working with segregationist senators. By all appearances, that spat may not be over yet—Booker said recently he felt disrespected by Biden’s remarks, as well as his suggestion that Booker should apologize for calling him out on the tone-deaf comments. Though Biden ultimately said he regretted touting his work with segregationist senators as a valuable asset, that admission came only after an ugly war of words with Booker in which he suggested the New Jersey senator “should apologize” for implying he was racist. In watching Harris successfully land a major blow to Biden in the first debate over his past position on busing, it will be interesting to see if Booker adopts a similar pre-emptive strategy.