Answer: What a shame! Since you're growing this determinate tomato variety in a container, the most likely culprit is early blight. The fungal spores blow in on the wind, so it's hard to escape their effects. You can try to keep the new growth from infection by spraying all surfaces with a copper-based fungicide. Remove the affected leaves only - leave as many as you can to keep pumping sugar into the fruit, and you should be able to harvest some! Best of luck!
Q&A Library Searching Tips