This is a tragedy in three acts.

The setting is a huge, festively decorated L-shaped room in Chelsea’s Clocktower Commons. Adobe walls are adorned with colorful murals, including one of a lady kneading dough who seems ridiculously overjoyed that a man is presenting her with a pink shawl. Bright green and red lamps hang over tables between high-backed booths. The sparkling long bar is a perfect spot for sampling Mexican beers. Picture windows frame an actual fountain in a courtyard—appropriately, since the place is called Las Fuentes (“The Fountains”).

Act 1 takes place a few weeks after its June opening, on one of the evenings of Sounds & Sights on Thursday Nights. The restaurant is bustling with the feel of a party to which everyone’s welcome. It’s run by the Aguirre family, who operate La Fuente in Ypsilanti (confusingly, a singular “fountain”).

The menu is astounding in its range and diversity. It includes familiar fare such as tacos, burritos, and enchiladas but also some authentic dishes rarely seen in these parts.

The chicken in my enchilada is as succulent as the meat in a hearty chicken soup made from scratch. In everything sampled on the first visit, the ingredients are fresh and full of home-cooked goodness. I could picture my Mexican grandmother, if I had one, cooking in her own kitchen just to make this wholesome food especially for me.

The service is enthusiastic and attentive. The prices are extremely reasonable.

At dessert, the sopaipillas are the best I’ve ever tasted—soft wispy puffs of thin fried dough, drizzled with honey and nestled on a plate speckled with cinnamon sugar. They literally melt in your mouth. I plan to write that Chelsea’s first Mexican restaurant in anyone’s memory may in fact be the best Mexican eatery in Washtenaw County—and as good as any place in southwest Detroit’s Mexicantown area.

Act 2 is a messy intermezzo full of discordant notes. I return less than a month after my first visit for a sampling of lunchtime fare. There’s an odd sign in the window that says the restaurant is not affiliated with any other restaurant in the area. The menu has changed. Gone are some of the specials and more unusual items; newly included are pedestrian appetizers such as Buffalo wings and potato skins.

The cauliflower rellenos—tangy pieces of cauliflower cooked just beyond al dente, in a savory red sauce and slathered with cheese—suit a vegetarian’s palate. And there is an unusual tortilla soup: thick with tender chicken, strips of tortilla, and a chunk of corn on the cob—all in a brisk cilantro-flavored broth.

A chalupa piled up with fresh lettuce and a few strands of cabbage is pretty. A gooey cheese enchilada is the Mexican version of the perfect grilled-cheese sandwich. A chili relleno is spicy, dark, and tender, but a tamale is just ordinary.

The chicken and beef are still tender and texturally magnificent. My garlic shrimp needs another flavoring besides garlic.

Bland Spanish rice covers half the plates. The refried beans seem less fresh.

The sopaipillas still shine. The churros are little cinnamon twists with bits of chocolate drizzled on them. The buñuelos—pieces of fried tortillas with cinnamon and sugar—are a third variation on the same theme.

The service is indifferent. A cook comes out and curses in Spanish at the waiter beside our table. The desserts arrive without individual plates. Worst of all, the waiter explains that the menu always includes daily specials and mentions the two offered that day—but not until after we have finished our desserts.

I learn that the Aguirres have been bought out and that the new owners run a chain called Pancho Villa. The other outlets are all in Virginia; this is the first of several planned for Michigan. I’m told this place will eventually be renamed accordingly.

Act 3 takes place on a drizzly fall day. The place is almost deserted as our group arrives after 1 p.m. for lunch. It’s still called Las Fuentes, but it resembles the place I first visited about as much as this gloomy afternoon resembles that bright hot summer evening.

On this visit, the corn chips seem a little stale and need salt. A cheese dip appetizer is flavorful and creamy but speckled with chilies that aren’t fresh. Our waiter looks shocked when we ask for fresh chilies, but he does bring them.

The huevos rancheros, drowning in a vinegary-tasting sauce, are fine. A combo of a beef taco, burrito, and chili relleno is loaded with that familiar vinegary ground beef. The tortilla soup looks the same, but the chicken isn’t. A chicken flauta is not thin and crisp—it’s more like a huge fried burrito stuffed with dry, overcooked meat and little else. And a chicken breast, seasoned apparently only with chili powder, has the look and texture of a rubber chicken.

The service is atrocious. The waiter never even asks whether we want our soft drinks and ice tea refilled—the glasses just sit there empty. The desserts again arrive without separate plates, and when we ask we first get one saucer (not a plate) and have to ask again before we are brought other saucers masquerading as dessert plates. Fried ice cream sits atop cornflakes and is slobbered with honey and cinnamon—comfort food. The churros have been transformed into apple-filled pastries that remind me of Hostess apple pies.

And, most tragically, the marvelous sopaipillas have been replaced by thick, bland chunks of overcooked dough that are so leathery you have to work overtime to chew and swallow them.

I want to cry. What happened to the wonderful new restaurant Chelsea deserves? How could something so good go so bad so fast?