Here’s what terrifies your neighborhood theater critic: Reviewing the final third of a trilogy without having seen the first two parts.

No worries.

Tom Dudzick’s “Last Mass at St. Casimir’s” — which follows his autobiographical “Over the Tavern” and “King o’ the Moon” — stands on its own as a warm, charming family comedy and (from what I’ve gathered) as a satisfying conclusion to the series about a working-class, bar-owning Polish family in Buffalo, N.Y.

Richmond Hill Players in Geneseo, Ill., which performed the first two parts in 2005 and ‘07, finishes strong, thanks to the return of several performers.

The conclusion finds the waning days of both the Pazinski family-owned Chet’s Bar & Grill and the titular Catholic church in the neighborhood. Set in 1977, the “blizzard of the century” traps siblings Eddie (Kevin Maynard), Annie (Ryan Mosher-Ohr), Georgie (Ryan Anderson) and Rudy (Nicholas Waldbusser) along with their mother (Angela Rathman), who still lives with developmentally disabled son Georgie, above the tavern.

The script and the performances are warm without being overly sentimental, humorous without major sight gags and realistic without being boring.

All of the performers in this rendition do a fine job, especially capturing the rapport of adult children. Mosher-Ohr, who played Annie in the second installment as well, has the upstate New York accent nailed down, and Maynard, Anderson and Waldbusser give credible performances while looking a bit like siblings to boot. (Maynard also played Eddie in the first installment, while Anderson — who walks the fine line of playing someone with special needs without going over the top — had the Rudy part in the first play.)

Give the most credit to Rathman, who has played mama Ellen throughout all three pieces. She brings a matter-of-fact realism to the role of the mother that is irresistible.

Also a constant in these shows has been director Susan Simosky, who brings the perfect touch to this familial story. She accomplishes a mean feat by making us believe we’re observing a family in front of us rather than actors on a stage.

Kudos as well to set designer Alexander Hamilton, who created a legitimate-looking bar along one wall of the theater, complete with neon Schlitz and lighted Old Style signs.

I loved the Pazinski family and just wish I would have visited them earlier.