Three teams will battle it out for two places with bonus-point wins over struggling Treviso likely to secure a runners-up spot.
Teams: Stade Francais, Munster, Leicester Tigers, Benetton Treviso
Stade Francais
Champions Cup record: P79 W52 D1 L26
Best finish: Runners-up (2001, 2005)
What's hot: The Top 14 champions boast one of the strongest packs in France, with Willem Alberts adding further power. Jules Plisson is a talented fly-half and could strike an effective partnership with Will Genia.
What's not: Stade's lack of squad depth is underlined by their poor start to the season. Competing on two fronts could be a struggle.
What's changed: World Cup stars Genia and Alberts have moved to the French capital while former Wallaby Digby Ioane has joined Japan side Honda Heat.
Key player: Sergio Parisse
Munster
Champions Cup record: P144 W100 D1 L43
Best finish: Winners (2006, 2008)
What's hot: CJ Stander is now Irish-qualified and has been putting his hand up for selection with some eye-catching performances. Ian Keatley is a quality goal-kicker and the trio of Francis Saili, Keith Earls and Simon Zebo have the potential to cut teams open.
What's not: Peter O'Mahony's long-term injury lay-off compounds the departure of Paul O'Connell and leaves Munster without their two leaders, while Tommy O'Donnell's absence is another blow. The famous Thomond Park roar also isn't what it used to be as attendances have dropped at the Limerick venue.
What's changed: Ireland great O'Connell, JJ Hanrahan and Donncha O'Callaghan have left the province. All Black Saili is the most high-profile arrival while Argentina full-back Lucas Gonzalez Amorosino comes in on a short-term deal after Felix Jones was forced to retire.
Key player: Francis Saili
Leicester Tigers
Champions Cup record: P130 W84 D5 L41
Best finish: Winners (2001, 2002)
What's hot: The Tigers have made a strong start to the season despite being without a number of first-teamers. Fly-half Owen Williams is in fine form and second rows Mike Williams and Mike Fitzgerald have both made positive impacts since arriving at Welford Road.
What's not: The Tigers may be winning but tries are in short supply. They've scored just four in as many games.
What's changed: There have plenty of comings and goings over the close season, with former Tiger Aaron Mauger has taken over as head coach and Brendon O'Connor, Williams, Peter Betham and Telusa Veainu all arrive from Super Rugby and former Springbok captain Jean de Villiers joins in December. Pablo Matera returns to Argentina with Julian Salvi, Jamie Gibson and Geoff Parling all moving to Premiership rivals.
Key player: Owen Williams
Benetton Treviso
Champions Cup record: P102 W19 D1 L82
Best finish: Pool stages
What's hot: Treviso haven't had much to shout about this season but Edoardo Gori remains a quality scrum-half and former England lock Tom Palmer brings bags of experience.
What's not: The Italians are on a 14-game losing streak in the PRO12 and have a tendency to throw in the towel when things aren't going to plan.
What's changed: The departures of Italy pair Michele Campagnaro and Simone Favaro have weakened Treviso even further. They have won just three Champions Cup games in the past five seasons.
Key player: Edoardo Gori