The 2014-15 UEFA Champions League formally starts Tuesday at various sites throughout Europe. Although qualifying phases began in July, many view the group stages as the official beginning of a new season. Subplots are plentiful ahead of the opening matchday, notably the absence of three-time winners Manchester United; and will Real Madrid, having finally captured their 10th European Cup title (La Décima) in May, become the first team in the modern era to successfully defend their title? Here’s a look at what to expect from Groups A-D, who all have Matchday 1 on Tuesday…

Group A

Atlético Madrid were roughly 90 seconds away from a first-ever Champions League triumph, only for city rivals Real to get a stoppage-time equalizer and an extra-time victory. El Atleti‘s road back to the Final starts at Greek champions Olympiacos, who reached the Round of 16 last year and hope to go one step further. Juventus will aim for a better finish than third place in the group stage, while Malmö could spring a surprise or two as group underdogs.

Group B

Before Real Madrid’s win in May, Los Blancos had come up short in three straight semifinals; before then, they endured six straight Round of 16 exits. Is 2014 the beginning of a dynasty? Liverpool are back in the UCL after five seasons, with a squad eager to prove they have returned to Europe’s elite. Basel is also seeking another trip to the knockout rounds, and Ludogorets Razgrad, who began their campaign in the second qualifying round, needed penalties to see off 1986 winners Steaua and advance to this phase.

Group C

Three of the clubs in this group have made the Final before; Zenit St. Petersburg is the odd one out as of now, but have many players with experience in big matches. Benfica haven’t won the European Cup in over 50 years; can the Portuguese champions end that drought in 2015? Bayer Leverkusen want to make amends after a 6-1 aggregate loss to PSG in the last 16 of 2013/14. Monaco is the big question in this group; having finished second in the French league last year with Colombians James Rodriguez and Radamel Falcao, how will they fare without those two?

Group D

For the third time in four seasons, Arsenal and Borussia Dortmund are drawn in the same group. Both clubs have enjoyed recent domestic success but are ready to extend that good fortune to the Champions League. Many pundits will probably predict those two to advance to the last 16, but you can never write off Galatasaray, who claimed Turkey’s automatic group entry spot because of Fenerbahce’s ban. Anderlecht aren’t new to this stage of the UCL, but can they cause a few shock results and make the knockout round?

Click here for my preview of Groups E-H.