Connacht enjoyed a fairytale 2015-16 Pro12 season that culminated in a wonderful 20-10 victory over Irish rivals Leinster in May's final.
Leinster, the four-time champions, were outplayed as Connacht capped a brilliant campaign that included a highest league finish of second.
But much has changed since May as the rest of the league looks to ensure that Pat Lam's men are nothing more than one-hit wonders.
LAM'S MEN TO THE SLAUGHTER?
The good news for Connacht is that head coach Lam is seemingly here to stay despite speculation linking him as a future successor to Ireland coach Joe Schmidt.
The bad news is that influential centre Robbie Henshaw has jumped ship to Leinster, while influential trio Rodney Ah You, Aly Muldowney and AJ MacGinty have all departed for pastures new.
South African fly-half Marnitz Boshoff and Leinster full-back Cian Kelleher have arrived but it promises to be a tricky task to defend the title.
IRISH EYES TO SMILE ON LEINSTER, ULSTER?
It was disappointment for Leinster in the final, but they topped the table last time out and Henshaw - likened by many to the legendary Brian O'Driscoll - adds star quality.
The forced retirement of Luke Fitzgerald due to a neck injury sustained in the final is a blow, but Leinster will be favourites to get their hands on the trophy.
Ulster have also strengthened with Charles Piutau arriving following a brilliant season in the Premiership with Wasps, while South Africa flanker Marcell Coetzee adds strength in the pack.
Munster complete the Irish line-up, but little is expected from a team that owes the Irish Rugby Football Union a reported EUR6million.
TOWNSEND SET FOR WARRIORS SWANSONG
Gregor Townsend led Glasgow Warriors to an unexpected Pro12 title in the 2014-15 season and the Scottish side enjoyed a run to the semis last term.
Those impressive performances have seen Scotland turn to Townsend to replace Vern Cotter from June 2017.
Influential duo Leone Nakarawa and Taqele Naiyaravoro have left, but the Warriors will still be expected to challenge to send Townsend off on a winning note.
Edinburgh were ninth last term, but the addition of Duncan Weir to a team boasting Ross Ford and Willem Nel may help them improve this time around.
Scarlets' fifth-place finish was the best the Welsh regions could muster last season, and Jonathan Davies' return coupled with the signing of Rhys Patchell means they are well equipped for a top-four push.
Bradley Davies has left Wasps to return to Wales by joining Ospreys on a National Dual Contract, but the loss of last season's standout performer Sam Underhill to injury for the first few months of the campaign is a concern.
Dragons powerhouse forward Taulupe Faletau has departed for Bath, while Danny Wilson shipped out 15 players in an overhaul at Cardiff Blues.
MORE WOE IN ITALY?
The two Italian teams, Zebre and Treviso, propped up the league last season with the former finishing 11th and earning European Champions Cup rugby.
Josh Furno and Carlo Festuccia have signed on, but last season's placing was their best in Pro12 and it is likely to be another season of struggle.
Tito Tebaldi, Tommasso Allan, Tommaso Benvenuti and Michael Tagicakibau have strengthened Treviso.